Benzothiazin-3-one compound and intermediate therefor

ABSTRACT

A medicine which contains as an active ingredient a benzothiazin-3-one-compound represented by the formula (1): 
     
       
         
         
             
             
         
       
     
     (wherein n is 3 or 4; R represents ethyl or hydrogen; and R 1  represents hologeno, alkoxy, haloalkyl, or haloalkoxy) or a pharmaceutically acceptable salt thereof. It is useful as a therapeutic or preventive agent for arthrosis deformans, chondrodegenerative discases such as chronic articular rheumatism, cancers, gingivitis, etc. Also provided are an intermediate for the compound and a process for producing the compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No.10/598,516, filed Jun. 18, 2007 (now allowed); which is a 371 ofPCT/JP05/03821, filed Feb. 28, 2005; the entire disclosure of each ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a novel benzothiazin-3-one compound ora pharmaceutically acceptable salt thereof, which is useful as a matrixmetallo-proteinase inhibitor, an intermediate for production of thecompound and a process for producing the compound.

BACKGROUND ART

Extracellular matrix constituting connective tissues, represented bycollagen and proteoglycan is metabolized by a group of proteasesreferred to as matrix metallo-proteinase (hereinafter abbreviated asMMPs in some cases). As MMPs, there are known at present 23 enzymes suchas collagenase (referred to also as matrix metallo-proteinase-1 orMMP-1), gelatinase A (referred to also as matrix metallo-proteinase-2 orMMP-2), stromelysin (referred to also as matrix metallo-proteinase-3 orMMP-3), gelatinase B (referred to also as matrix metallo-proteinase-9 orMMP-9), collagenase 3 (referred to also as matrix metallo-proteinase-13or MMP-13) and membrane-bound matrix metallo-proteinase-1 (e.g. MT1-MMPand MMP-14). The amount of the extracellular matrix in a living body isstrictly controlled by endogenous inhibitors of MMPs (e.g. TIMP (tissueinhibitor of matrix metallo-proteinase)). However, when such a balanceis disturbed, the enzyme activity of MMP is abnormally enhanced,resulting in various diseases accompanied by the destruction ofconnective tissues as symptom.

As the diseases, there are exemplified arthrosis deformans and chronicarticular rheumatism which are accompanied by the destruction ofarticular cartilage. As MMPs which participate in arthrosis deformansand chronic articular rheumatism, there are exemplified stromelysin andcollagenase 3 etc. (see Annals of the Rheumatic Diseases. 59(6):455-61(2000) and Journal of Clinical Investigation. 99(7):1534-45 (1997)).

In addition, MMPs are enzymes capable of decomposing basement membraneand participate in the infiltration of cancerous cells into vascularendothelium from peripheral tissues, namely, cancer metastasis. As suchMMPs, gelatinases A and B are exemplified (see Pancreas. 24(2):169-78(2002)).

The therapeutic or preventive effect of MMP inhibitors on theabove-exemplified diseases is revealed by J. Exp. Med., 182, 449-457(1995), Inflamm. Res, 44, S117-S118 (1995), British J. Pharmacol., 121,540-546 (1997), Inflamm. Res, 49, 144-146 (2000), Am. J. Clin. Oncol.,22, 247-252 (1999), Osteoarthritis and Cartilage, 10, 785-791 (2002),etc. Therefore, MMP inhibitors are considered effective as therapeuticor preventive agents for chondrodegenerative diseases (e.g. arthrosisdeformans, chronic articular rheumatism), cancers, etc.

As MMP inhibitors, many compounds are known (see Exp. Opin. Ther.Patents, 8, 259-282 (1998)). There may be exemplified2-benzylbenzothiazin-3-one compounds (International Publication No.WO00/63197 pamphlet and Japanese Patent Unexamined PublicationJP-A-2002-12876).

However, an MMP inhibitor capable of exhibiting a more remarkable effectin a living body is desired even now.

On the other hand, a process for producing a benzothiazin-3-one compoundis disclosed in International Publication No. WO00/63197 pamphlet and isthus well known. In addition, there have been reported a process inwhich an α-bromocarboxylic acid derivative is condensed with athiophenol derivative in DMF (see Chem. Pharm. Bull., 39, 2888 (1991))and a process in which the hydroxyl group of an α-hydroxycarboxylic acidis converted to a trifluoromethanesulfonyloxy group in acetonitrile,followed by condensing with a nucleophile in one pot (see Tetrahedron.Asymmetry, 3, 715 (1992)). However, there has been a desire for aprocess for efficient production of an optically activeα-phenylthiocarboxylic acid derivative with little racemization.

As a process for producing an α-hydroxycarboxylic acid as anintermediate for production of the above-mentioned benzothiazin-3-onecompound, there are known, for example, the process using baker's yeastdisclosed in Japanese Patent Unexamined Publication JP-A-10-84987; theprocess of carrying out catalytic asymmetric hydrogenation which isdisclosed in Japanese Patent Unexamined Publication JP-A-10-120621, witha hydantoin derivative disclosed in Japanese Patent UnexaminedPublication JP-A-2000-309575; the process using Grignard reaction of achiral epoxide compound disclosed in Japanese Patent UnexaminedPublication JP-A-2000-37761; and the process using DIP-Cl and disclosedin Tetrahedron Lett., 39, 5501 (1998). However, there has been a desirefor a process for producing an α-hydroxycarboxylic acid with a highoptical purity in higher yield.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a novel agent usefulas, for example, a therapeutic or preventive agent forchondrodegenerative diseases (e.g. arthrosis deformans, chronicarticular rheumatism), cancers, etc., an intermediate for production ofthe agent and a process for producing the agent.

The present inventors earnestly investigated in order to achieve theabove object, and consequently found that the benzothiazin-3-onecompound of the present invention exhibits an excellent pharmacologicalactivity on an arthrosis deformans animal model when orallyadministered. Furthermore, the present inventors found that saidcompound acts as a prodrug since it is converted to a highly activecarboxylic acid compound by hydrolysis of its ethoxycarbonyl group inits metabolism in a living body.

In addition, the present inventors found a process for producing anintermediate for production of the benzothiazin-3-one compound from anα-hydroxycarboxylic acid derivative in high yield, a method for opticalresolution of the starting α-hydroxycarboxylic acid, and the like.

The present invention has been accomplished on the basis of the abovefindings.

The present invention relates to the benzothiazin-3-one compounds orpharmaceutically acceptable salts thereof, which are useful as MMPinhibitors and are described below in [1] to [22]:

[1] A benzothiazin-3-one compound represented by the formula (1):

wherein n is 3 or 4; R is an ethyl group or a hydrogen atom; and R¹ is ahalogen atom, an alkoxy group, a haloalkyl group or a haloalkoxy group,or a pharmaceutically acceptable salt thereof;

[2] A benzothiazin-3-one compound according to [1], characterized bybeing represented by the formula (1S):

wherein n, R and R¹ are as defined above, or a pharmaceuticallyacceptable salt thereof;

[3] A benzothiazin-3-one compound or a pharmaceutically acceptable saltthereof according to [1] or [2], wherein R¹ is a fluorine atom, achlorine atom, a methoxy group, a trifluoromethyl group or atrifluoromethoxy group;

[4] A benzothiazin-3-one compound or a pharmaceutically acceptable saltthereof according to any one of [1] to [3], wherein R is an ethyl group;

[5] A benzothiazin-3-one compound or a pharmaceutically acceptable saltthereof according to any one of [1] to [3], wherein R is a hydrogenatom;

[6] A compound or a pharmaceutically acceptable salt thereof accordingto [4], wherein the compound represented by the formula (1) is selectedfrom the following group of compounds: ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxy-phenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate,ethyl2-[3-(4-chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate,ethyl2-[3-(4-fluoro-phenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate,ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-[3-(4-trifluoromethylphenyl)propyl]-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate,ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-[3-(4-trifluoromethoxyphenyl)propyl]-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylateand ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate;

[7] A compound or a pharmaceutically acceptable salt thereof accordingto [1], wherein the compound represented by the formula (1) is (−)-ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate;

[8] A compound or a pharmaceutically acceptable salt thereof accordingto [5], wherein the compound represented by the formula (1) is selectedfrom the following group of compounds:4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxy-phenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid,2-[3-(4-chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid,2-[3-(4-fluoro-phenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid,4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-[3-(4-trifluoromethylphenyl)propyl]-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid,4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-[3-(4-trifluoromethoxyphenyl)propyl]-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid and4-[2-(hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid;

[9] A compound or a pharmaceutically acceptable salt thereof accordingto [1], wherein the compound represented by the formula (1) is(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid.

The present invention also relates to the pharmaceutical compositions orremedies described below in [10] to [14]:

[10] A pharmaceutical composition comprising a benzothiazin-3-onecompound or a pharmaceutically acceptable salt thereof according to anyone of [1] to [9] as an active ingredient;

[11] A matrix metallo-proteinase inhibitor comprising abenzothiazin-3-one compound or a pharmaceutically acceptable saltthereof according to any one of [1] to [9] as an active ingredient;

[12] A remedy or prophylactic for chondrodegenerative diseases orinflammatory diseases comprising a benzothiazin-3-one compound or apharmaceutically acceptable salt thereof according to any one of [1] to[9] as an active ingredient;

[13] A cancer metastasis suppressant comprising a benzothiazin-3-onecompound or a pharmaceutically acceptable salt thereof according to anyone of [1] to [9] as an active ingredient;

[14] A pharmaceutical composition for oral administration comprising abenzothiazin-3-one compound or a pharmaceutically acceptable saltthereof according to [4], [6] or [7].

In addition, the present invention relates to the intermediates forproduction of the compound of the formula (1) described below in [15] to[22]:

[15] A compound represented by the formula (2):

wherein n and R¹ are as defined in the formula (1) and R² is an alkylgroup of 2 or 3 carbon atoms, a 4-nitrobenzyl group or a2,2,2-trichloroethyl group;

[16] A compound according to [15], wherein the alkyl group of 2 or 3carbon atoms is an ethyl group;

[17] A compound according to [15] or [16], which has an S-configuration;

[18] A compound according to [15] or [16], which has an R-configuration;

[19] A compound represented by the formula (3):

wherein n and R¹ are as defined in the formula (1) and R¹⁰ is a hydrogenatom, an alkyl group of 1 to 6 carbon atoms, a 4-nitrobenzyl group or a2,2,2-trichloroethyl group;

[20] A compound according to [19], wherein the alkyl group of 1 to 6carbon atoms is a methyl group or an ethyl group;

[21] A compound according to [19] or [20], which has an S-configuration;

[22] A compound according to [19] or [20], which has an R-configuration.

Further, the present invention relates to the processes for producing abenzothiazin-3-one compound according to any one of [1] to [9] or anintermediate for production of the compound which are described below in[23] and [24]:

[23] A process for producing an optically active form of a compoundrepresented by the formula (4):

wherein n, R and R¹ are as defined above and R⁵ is a hydroxyl group, analkoxy group or a hydroxyamino group, characterized by oxidizing thecompound with a Water-modified Sharpless reagent,(−)-8,8-(dichlorocamphorylsulfonyl)oxaziridine or(+)-8,8-(dichlorocamphorylsulfonyl)oxaziridine;

[24] A production process according to [23], characterized in that theoxidizing agent is (+)-8,8-(dichlorocamphorylsulfonyl)oxaziridine andthat the optically active form is represented by the formula (4S):

wherein n, R, R¹ and R⁵ are as defined above.

Still further, the present invention relates to the processes forproducing an intermediate for production of a benzothiazin-3-onecompound described in [25] and [26] and the intermediate for productiondescribed in [27]:

[25] A process for producing a compound represented by the formula (9):

wherein n, R¹ and R are as defined above and X¹ and R²′ are as definedbelow, characterized by reacting a compound represented by the formula(5):

wherein n and R¹ are as defined above and R^(2′) is a protective groupfor carboxyl group or a group represented by the formula (6):

wherein R³ is an alkyl group or an aryl group, with a brominatingreagent or a trifluoromethanesulfonylating reagent to convert to acompound represented by the formula (7):

wherein n, R¹ and R²′ are as defined above and X² is a bromine atom or atrifluoromethanesulfonyloxy group, and then reacting this compound witha compound represented by the formula (8):

wherein X¹ is a halogen atom or a nitro group and R is as defined above,or a salt thereof in the presence of a base.

[26] A production process according to [25], wherein X¹ is a bromineatom or a nitro group and X² is a trifluoromethanesulfonyloxy group;

[27] A compound represented by the formula (3′):

wherein n, R¹ and R³ are as defined above and X⁵ is a bromine atom or ahydroxyl group.

Still further, the present invention relates to the processes forproducing an optically active α-hydroxycarboxylic acid described in [28]to [30]:

[28] A process for producing an optically active form of a compoundrepresented by the formula (10):

wherein n and R¹ are as defined above, characterized by opticallyresolving a racemic modification of the compound of the formula (10) byadding an optically active α-tolylethylamine to the racemic modificationin an inert solvent to form diastereomers;

[29] A production process according to [28], wherein the opticallyactive α-tolylethylamine is (−)-α-tolylethylamine and the opticallyactive form of a compound represented by the formula (10) is a compoundwith an S-configuration represented by the formula (10S):

wherein n and R¹ are as defined in the above formula (10), or a saltthereof.

[30] A production process according to [28], wherein the opticallyactive α-tolylethylamine is (+)-α-tolylethylamine and the opticallyactive form of a compound represented by the formula (10) is a compoundwith an R-configuration represented by the formula (10R):

wherein n and R¹ are as defined in the above formula (10), or a saltthereof.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a graph showing the result of oral-absorbability evaluationtest on rats.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present specification, the halogen atom for R¹ includes fluorineatom, chlorine atom, bromine atom and iodine atom. The halogen atom forR¹ is preferably a fluorine atom or a chlorine atom.

In the present specification, the alkoxy group for R¹ is a linear orbranched alkoxy group of 1 to 4 carbon atoms. Specific examples thereofare methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxygroup, 1-methyl-1-propoxy group, 1-methyl-2-propoxy group,2-methyl-1-propoxy group, 2-methyl-2-propoxy group, etc. The alkoxygroup for R¹ is preferably a methoxy group.

In the present specification, the haloalkyl group for R¹ is a linear orbranched haloalkyl group of 1 to 4 carbon atoms having 1 to 5 halogenatoms which are the same or different. Specific examples thereof aretrifluoromethyl group, 2,2,2-trifluoroethyl group, 2-fluoroethyl group,etc. R¹ is preferably a trifluoromethyl group.

In the present specification, the haloalkoxy group for R¹ is a linear orbranched haloalkoxy group of 1 to 4 carbon atoms having 1 to 5 halogenatoms which are the same or different. Specific examples thereof aretrifluoromethoxy group, 2,2,2-trifluoroethoxy group, 2-fluoroethoxygroup, etc. R¹ is preferably a trifluoromethoxy group.

In the present specification, the alkyl group for R³ is a linear orbranched alkyl group of 1 to 4 carbon atoms. Specific examples thereofare isopropyl group, isobutyl group, etc. The aryl group for R³ includesphenyl group, 1-naphthyl group, 2-naphthyl group, benzyl group, etc.

A first aspect of the present invention is directed to a compoundrepresented by the above formula (1) or a pharmaceutically acceptablesalt thereof.

The compound of the formula (1) has an asymmetric carbon atom at the2-position in its benzothiazine skeleton, and the formula (1) alsorepresents optical isomers due to the asymmetric carbon atom. Thecompound of the formula (1) is preferably an optically active substance,and the configuration relating to the asymmetric carbon atom ispreferably an S-configuration (in the present specification, the symbolsR and S for expressing the configuration relating to the asymmetriccarbon atom are used according to the IUPAC rules of organic chemistrynomenclature). Especially preferable examples of the optically activesubstance are (−)-ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxy-phenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylateand(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid.

The compound represented by the formula (1) of the present invention maybe produced by a proper combination of a well-known process such as theprocess disclosed in International Publication No. WO00/63197 pamphlet,a process based thereon and the process of the present invention.Specific examples of production process of the compound are given below.

When R is an ethyl group in the formula (1), the compound may beproduced according to any of the following production processes 1 to 4.

Production Process 1

wherein n and R¹ are as defined above; X³ and X⁴ are independently aleaving group; and R²″ and R⁴ are independently a protective group forcarboxyl group.

In the production process 1, as the protective groups for carboxyl grouprepresented by R²″ and R⁴, there are exemplified protective groups whichare generally used by those skilled in the art and are removable underconditions under which the ethyl ester is not hydrolyzed. Specificpreferable examples thereof are protective groups such as benzyl group,p-nitrobenzyl group, p-methoxybenzyl group, tert-butyl group, etc. Theseprotective groups are described in T. W. Green, “Protective Groups inOrganic Synthesis”, 3rd ed., John Wiley & Sons, Inc. (1999) (hereinafterreferred to as Green reference). As the leaving groups represented by X³and X⁴, there are exemplified halogen atoms such as bromine atom andiodine atom and sulfonyloxy groups. The sulfonyloxy groups includehaloalkylsulfonyloxy groups (e.g. trifluoromethanesulfonyloxy group),alkylsulfonyloxy groups (e.g. methanesulfonyloxy group), andarylsulfonyloxy groups (e.g. p-toluenesulfonyloxy group). X⁴ ispreferably a bromine atom.

(Step 1)

compound of the formula (1-3) may be produced by reacting a compound ofthe formula (1-1) with a compound of the formula (1-2) in an inertsolvent such as acetonitrile or THF in the presence of a suitable basesuch as N-methylmorpholine or triethylamine.

(Step 2)

The protective group for carboxyl group (i.e. the group represented byR²″) of the compound of the formula (1-3) may be removed underconditions under which the ethyl ester is not hydrolyzed and which areemployed in the method described in the above-mentioned “Greenreference” and the like. For example, when R², is a p-nitrobenzyl group,a compound of the formula (1-4) may be produced by reacting the compoundof the formula (1-3) with a metal such as iron or zinc without a solventor in a hydrophilic solvent such as THF in the presence of an acid suchas acetic acid or ammonium chloride.

(Step 3)

compound of the formula (1-5) may be produced by reacting the compoundof the formula (1-4) with a glycine ester in an inert solvent such asmethylene chloride in the presence of a base such as triethylamine bythe use of a condensing agent such as N,N′-dicyclohexylcarbodiimide(DCC), 1-ethyl-3-(3′-dimethylaminopropyl)carbodiimide (EDC) or carbonyldiimidazole (CDI). In this case, if necessary, an activator may beadded. The activator includes, for example, N-hydroxybenzotriazole(HOBt) and N-hydroxysuccinimide (HOSu).

(Step 4)

benzothiazin-3-one compound of the formula (1-6) may be produced byadding a metal catalyst and a ligand therefor to the compound of theformula (1-5) in an inert solvent such as toluene in the presence of abase such as cesium carbonate to subject the compound of the formula(1-5) to intramolecular amidation. This procedure may be carried outaccording to, for example, the method described in Buchwald et al., J.Am. Chem. Soc., Vol. 119, p 8451-8458 (1997). Specific examples of themetal catalyst are tris(dibenzylideneacetone)palladium(0),tetrakis(triphenylphosphine)palladium(0), etc. The ligand includes, forexample, 1,1′-bis(diphenylphosphino)ferrocene (dppf) andtris(o-tolylphosphine). An especially preferable example of the ligandis dppf.

The inert solvent used here is not particularly limited. For example,toluene may be used as the inert solvent. The inert solvent may be usedin a volume of 10 to 50 ml, preferably 30 ml to 40 ml, per g of thestarting material. Although the reaction temperature is not particularlylimited, the reaction is usually carried out at 60° C. to 120° C. Thereaction time may be properly controlled by taking the disappearance ofthe starting material as an indication and is usually 3 hours to 8hours.

(Step 5)

compound of the formula (1-7) may be produced by a method properlychosen depending on the kind of ester portion of the compound of theformula (1-6). As the method, there is exemplified the method describedin R. C. Ralock, “Comprehensive Organic Transformations”, 2nd ed., VCHPublications Inc., New York (1999) (hereinafter referred to as Ralockreference). For example, when R⁴ is a tert-butyl group, an acid such astrifluoroacetic acid or hydrochloric acid may be used optionally in thepresence of a scavenger such as dimethyl sulfide, anisole or water, or aLewis acid such as boron trichloride may be used in an aprotic solventsuch as methylene chloride optionally in the presence of a sulfidecompound such as dimethyl sulfide. When R⁴ is a benzyl group, thecompound of the formula (1-6) may be hydrogenated in an inert solventsuch as ethanol in the presence of a catalyst such as palladium-carbon.When R⁴ is a p-nitrobenzyl group, the same method as the above methodadopted in the case of R⁴ being a benzyl group may be adopted, orreduction may be carried out in acetic acid in the presence of zinc oriron.

(Step 6)

After the activation of the carboxyl group of the compound of theformula (1-7), the resulting compound is reacted with hydroxylamine or ahydroxylamine derivative, whereby the compound of the formula (1-7) maybe converted to a compound of the formula (1-8) corresponding to theformula (1) in which R is an ethyl group. As a method for the activationof the carboxyl group, an amide linkage formation reaction generallyused by those skilled in the art is exemplified. This method isdescribed, for example, in “Ralock reference” or Nobuo Izumiya et al.,“Fundamentals and Practice of Peptide Synthesis”, Maruzen Co., Ltd.,1985. Specific examples of the method are an acid chloride method usingpivaloyl chloride or the like; a mixed acid anhydride method using analkyl chloroformate; an active ester method using a pentafluorophenylester or the like; and the like. After the carboxyl group is activatedby such a method, the resulting compound may be reacted withhydroxylamine or a hydroxylamine derivative. The compound of the formula(1-8) corresponding to the formula (1) in which R is an ethyl group maybe produced, for example, by treating the compound of the formula (1-7)with isobutyl chloroformate in an inert solvent such as THF in thepresence of a base such as N-methylmorpholine, and reacting the thustreated compound with a reagent such as O-trimethylsilylhydroxylamine,followed by desilylation of the resulting product with an acid such asdilute hydrochloric acid.

The compound of the formula (1-1) as an intermediate for production ofthe compound of the formula (1) is novel in itself.

The compound of the formula (1-1) may be produced, for example, by thefollowing process:

wherein n, R¹, R²″ and X³ are as defined above.

That is, when X³ is a sulfonyloxy group, the compound of the formula(1-1) may be produced by reacting a compound of the formula (1-9) withsulfonic acid anhydride or sulfonyl chloride in an inert solvent such asacetonitrile, methylene chloride or THF in the presence of a base suchas triethylamine.

On the other hand, when X³ is a bromine atom, the compound of theformula (1-1) may be produced by reacting a compound of the formula(1-9) with carbon tetrabromide and triphenylphosphine. The compound ofthe formula (1-1) may be produced also by reacting a compound of theformula (1-9) with thionyl bromide or phosphorus tribromide. Inaddition, when X³ is a bromine atom, the compound of the formula (1-1)may be produced also by the following process:

wherein n, R¹ and R²″ are as defined above.

That is, a compound of the formula (1-10) is diazotized with sodiumnitrite in an acidic aqueous solution (e.g. an aqueous hydrogen chloridesolution, an aqueous hydrogen bromide solution or an aqueous sulfuricacid solution), an organic acid solvent (e.g. acetic acid) or a mixtureof the aforesaid organic acid solvent and an inert organic solvent suchas toluene, dioxane, THF, or the like, and then the diazotized compoundis treated with an aqueous potassium bromide, sodium bromide or lithiumbromide solution or the like, whereby the compound of the formula (1-10)may be converted to a compound of the formula (1-11). The compound ofthe formula (1-11) may be converted to a compound of the formula (1-12)by esterification according to a method well known to those skilled inthe art. This method is described in International Publication No.WO00/63197 pamphlet, Synthesis, 583 (1999), or Tetrahedron Letters, 28,1993 (1987).

The compound of the formula (1-1) may be produced also by the well-knownprocess described in Tetrahedron Asymmetry, 6, 1919 (1995).

The compound of the formula (1-10) is a well-known compound and may beprepared by a process well known to those skilled in the art.Specifically, it may be synthesized by the process described inTetrahedron, 58, 6117 (2002).

The compound of the formula (1-9) may be produced, for example, by awell-known process or the process described in the working example inthe present specification. A process for producing an optically activeform of the compound of the formula (1-9) is explained in the productionprocess 6 or 7 hereinafter described, or the like.

The above-mentioned compound of the formula (1-6) may be producedaccording to the following production process 2.

Production Process 2

wherein n, R¹, R²″, R⁴ and X³ are as defined above.

Here, as the leaving group represented by X³, there are exemplifiedhalogen atoms such as bromine atom, iodine atom, etc.; and sulfonyloxygroups such as trifluoromethanesulfonyloxy group, methanesulfonyloxygroup, etc.

(Step 1)

compound of the formula (2-2) may be produced by reacting a compound ofthe formula (1-1) with a compound of the formula (2-1) in an inertsolvent such as THF in the presence of a suitable base such asN-methylmorpholine or triethylamine.

(Step 2)

compound of the formula (2-3) may be produced by reacting the compoundof the formula (2-2) with iron or zinc without a solvent or in a solventsuch as toluene in the presence of acetic acid or ammonium chloride tocarry out cyclization. In the production process 2, as the protectivegroup for carboxyl group represented by R²″, protective groups generallyused by those skilled in the art are exemplified. Specifically,protective groups such as methyl group, ethyl group, p-nitrobenzyl groupand the like are suitable.

(Step 3)

The compound of the formula (1-6) may be produced by reacting thecompound of the formula (2-3) with a compound of the formula (2-4) in aninert solvent such as dimethylformamide in the presence of a base suchas cesium carbonate, potassium carbonate or sodium hydride.

The compound of the formula (1-6) may be converted to the compound ofthe formula (1-8) by the method described in the above-mentionedproduction process 1.

A compound of the formula (3-3) corresponding to a compound of theformula (1) in which R is a hydrogen atom may be produced according tothe following production process 3.

Production Process 3

wherein R¹, R⁴ and n are as defined above, and R⁷ is a protective groupfor carboxyl group.

(Step 1)

A compound of the formula (3-2) may be produced by selectively removingR⁴ of a compound of the formula (3-1) and by a method similar to themethod described in the step 2 or step 5 in the above-mentionedproduction process 1. Here, a combination of the protective groupsrepresented by R⁴ and R⁷ may be any combination so long as it permitschoice of conditions under which R⁷ is not removed simultaneously withthe removal of R⁴. There are used, for example, a combination of anethyl ester and a (substituted) benzyl ester, a combination of an ethylester and a tert-butyl ester, a combination of a (substituted) benzylester and a tert-butyl ester, and a combination of a2,2,2-trichloroethyl ester and a tert-butyl ester. A combination ofp-nitrobenzyl ester and a tert-butyl ester, a combination of a benzylester and a tert-butyl ester, a combination of a 2,2,2-trichloroethylester and a tert-butyl ester, and the like are suitable. Reference to“Green reference” is sufficient to determine conditions for theprotection and deprotection in the case of each protective group.

The compound of the formula (3-1) may be produced in the same manner asin the production process 1.

(Step 2)

The compound of the formula (3-3) may be produced by converting theester portion of the compound of the formula (3-2) to a carboxyl groupby deprotection reaction. When R⁷ is an alkyl group such as ethyl group,the compound of the formula (3-2) may be hydrolyzed with an alkalineaqueous solution in an alcohol solvent such as ethanol. As the alkalineaqueous solution, there are exemplified an aqueous lithium hydroxidesolution, an aqueous potassium hydroxide solution, an aqueous sodiumhydroxide solution, an aqueous cesium hydroxide solution and an aqueousbarium hydroxide solution. Preferable examples thereof are an aqueouslithium hydroxide solution, an aqueous potassium hydroxide solution andan aqueous sodium hydroxide solution.

When the compound of the formula (3-2) is an optically active substancesynthesized by the production process described hereinafter or the like,racemization proceeds under conditions of, for example, theabove-mentioned hydrolysis with the alkaline aqueous solution, so thatthe optical purity of the compound of the formula (3-3) is remarkablydecreased in some cases. As a method for avoiding the progress of theracemization, there is exemplified a method of adding a 1% to 50%alkaline aqueous solution at a low temperature in 5 mM to 5Mtetrahydrofuran solvent. The reaction temperature is, for example, −25°C. to 15° C., preferably −20° C. to 5° C., more preferably −15° C. to−5° C. Preferable examples of the alkaline aqueous solution are anaqueous potassium hydroxide solution and an aqueous sodium hydroxidesolution. The number of equivalents of the alkali metal salt added is,for example, 1 to 10 equivalents, preferably 2 to 5 equivalents, morepreferably 2 to 3 equivalents.

It is also possible to produce the compound of the formula (3-3) whilekeeping the optical purity of the compound of the formula (3-2) asstarting material, by hydrolyzing the compound of the formula (3-2) witha hydrolase well known to those skilled in the art, such as lipase oresterase.

The intermediate for production such as the compound of the formula(1-3) as intermediate for production in the production process 1, thecompound of the formula (2-2) as intermediate for production in theproduction process 2, or a compound of the formula (5-7) as intermediatefor production in the production process 6 described hereinafter may beproduced according to the following production process 4. A productionprocess of a compound of the formula (9) based on the production process4 is also within the scope of the present invention.

Production Process 4

A process for producing a compound of the formula (9) as intermediatefor production of a benzothiazin-3-one compound such as a compound ofthe formula (1) is explained below in detail.

(Step 1)

compound of the formula (5) as starting material may be produced by theabove-mentioned production process and the process described in theworking example in the present specification.

In the formula (5), formula (7) and formula (9), n is preferably 3 or 4.

A compound of the formula (7) may be produced from the compound of theformula (5) by the following process:

wherein n, R¹, R²′ and X² are as defined above.

That is, when X² is a trifluoromethanesulfonyloxy group, the compound ofthe formula (7) may be produced by reacting the compound of the formula(5) with trifluoromethanesulfonic acid anhydride astrifluoromethanesulfonylating reagent in an inert solvent in thepresence of a base represented by organic amines such as triethylamine,N-methylmorpholine, etc. The base may be used usually in an amount of1.0 mole to 1.2 moles per mole of the starting material.

In the production process 4, preferable examples of R²′ are alkoxygroups of 1 to 6 carbon atoms, 4-nitrobenzyloxy group and2,2,2-trichloroethoxy group. Preferable examples of the aforesaid alkoxygroups are alkoxy groups of 2 or 3 carbon atoms.

Here, although the inert solvent is not particularly limited,acetonitrile, methylene chloride, THF and the like are preferably usableas the inert solvent. A more preferable inert solvent is acetonitrile.The inert solvent may be used in a volume of 3 ml to 5 ml per g of thestarting material. Although the reaction temperature is not particularlylimited, the reaction is usually carried out at −30° C. to −5° C. Thereaction time may be properly controlled by monitoring the disappearanceof the starting material and takes usually 0.5 hour to 2 hours.

On the other hand, when X² is a bromine atom, the compound of theformula (7) may be produced, for example, by the process described inthe above-mentioned production process 1, i.e., the process usingtriphenylphosphine and carbon tetrabromide as brominating agents.

When X² is a bromine atom, a well-known compound of the formula (4-1)(see Helvetica Chimica Acta, 40, 1812 (1957)) may be brominated with abrominating agent such as N-bromosuccinimide as follows after convertingthe hydrogen atom on the a carbon atom of the compound to a silyl enolether by the use of a base such as LDA and a silylating agent such astrimethylsilyl chloride (Tetrahedron Asymmetry, 6 1919 (1995)):

wherein n, R¹, R²′ and X² are as defined above.

(Step 2)

The compound of the formula (9) may be produced by condensing thecompound of the formula (7) with a compound of the formula (8) in aninert solvent in the presence of a base:

wherein n, R¹, R²′, R, X¹ and X² are as defined above.

When X² is a trifluoromethanesulfonyloxy group, the inert solvent is notparticularly limited. Preferable examples of the inert solvent areacetonitrile, methylene chloride and THF. A more preferable examplethereof is THF. Here, the step 2 may be carried out in the same systemas in the step 1 without isolating the product obtained in the step 1,i.e., the compound of the formula (7).

When the compound of the formula (5) and the compound of the formula (7)are optically active substances, employment of DMF or acetonitrilecauses partial racemization. However, it was found that employment ofTHF makes it possible to produce the compound of the formula (9) with ahigh optical purity in high yield without racemization.

The inert solvent may be used in a volume of 2 ml to 10 ml per g of thestarting material. As the base, there are exemplified organic aminessuch as N-methylmorpholine, triethylamine, etc. The base may be usedusually in an amount of 1.0 mole to 1.2 moles per mole of the startingmaterial.

The compound of the formula (8) may be used usually in an amount of 1.0mole to 1.2 moles per mole of the starting material. Although thereaction temperature is not particularly limited, the reaction isusually carried out at −50° C. to 5° C., preferably −20° C. to 0° C. Thereaction time may be properly controlled by monitoring the disappearanceof the starting material and takes usually 0.5 hour to 2 hours.

On the other hand, also when X² is a bromine atom, the compound of theformula (9) may be produced by the same process as above.

The compound of the formula (8) may be produced by a process well knownto those skilled in the art. A specific example of the process is theprocess described in the working example in the present specification.

The above-mentioned compounds of the formula (2) and the formula (3) asintermediates for production of the compound of the formula (1) arenovel compounds in themselves.

That is, the compound of the formula (2):

wherein n, R¹ and R² are as defined above, and the compound of thefollowing formula (3):

wherein n and R¹ are as defined in the formula (1) and R¹⁰ is a hydrogenatom, an alkyl group of 1 to 6 carbon atoms, a 4-nitrobenzyl group or a2,2,2-trichloroethyl group, are within the scope of the presentinvention.

Here, R¹ in the formula (2) and the formula (3) is preferably a methoxygroup. As the alkyl groups of 2 or 3 carbon atoms for R² in the formula(2), ethyl group, propyl group and isopropyl group are exemplified.

The alkyl group of 1 to 6 carbon atoms for R¹⁰ in the formula (3) is alinear or branched alkyl group. Specific examples thereof are methylgroup, ethyl group, propyl group, 1-methylethyl group, butyl group,1-methylpropyl group, 1,1-dimethylethyl group, pentyl group, hexylgroup, etc. R¹⁰ is preferably an alkyl group of 1 to 3 carbon atoms,more preferably a methyl group or an ethyl group.

The compounds of the formula (2) and formula (3) are compounds having anasymmetric carbon atom, and the present invention includes both amixture of optically active forms of each compound (a racemicmodification) and these optically active substances.

The optically active form of each compound may be produced by theprocess described hereinafter, and by the use of such an opticallyactive substance, an optically active compound of the formula (1) and anintermediate for production of this compound may be produced.

The compound of the formula (1) or a pharmaceutically acceptable saltthereof may be in the form of a solvate. The solvent in the solvateincludes, for example, alcohols such as methanol, ethanol, propanol,isopropanol, etc.; ketones such as acetone, etc.; ethers such astetrahydrofuran, dioxane, etc.; and water. Although the amount of thesolvent per molecule of the compound of the formula (1) is notparticularly limited, the solvate is, for example, one containing 0 to 3molecules (specifically ½ molecule, 1 molecule, 2 molecules or 3molecules) of the solvent.

The compound of the formula (1) and an intermediate for production ofthis compound may be purified by a method well known to those skilled inthe art. They may be purified, for example, by any of variousnormal-phase or reversed-phase column chromatographies using silica gel,an ion-exchange resin, molecular sieve or the like, high performanceliquid chromatography (HPLC) or recrystallization. A solvent for therecrystallization includes, for example, alcohol solvents such asmethanol, ethanol, 2-propanol, etc.; aprotic solvents such asdimethylformamide, dimethyl sulfoxide, etc.; ether solvents such asdiethyl ether, etc.; ester solvents such as ethyl acetate, etc.;aromatic hydrocarbon solvents such as toluene, etc.; ketone solventssuch as acetone, etc.; hydrocarbon solvents such as hexane, etc.;halogenated hydrocarbon solvents such as chloroform, dichloroethane,etc.; and mixed solvents thereof.

The compound of the formula (1) may be converted to a pharmaceuticallyacceptable salt as follows. As the pharmaceutically acceptable salt,base addition salts are exemplified. The base addition salts includeinorganic base salts such as sodium salt, potassium salt, cesium salt,ammonium salt, etc.; and organic base salts such as meglumine salt,tris(hydroxymethyl)aminomethane salt, triethylamine salt, lysine salt,etc.

The compound of the formula (1) is a compound having an asymmetriccarbon atom, and the present invention includes both a mixture ofoptically active forms of the compound (a racemic modification) andthese optically active substances. When the compound of the formula (1)or an intermediate for production of this compound is a racemicmodification, the racemic modification may be resolved into opticallyactive substances by the method described hereinafter in the presentspecification. Thus, the optically active substance may be producedaccording to the any of above-mentioned production processes 1 to 3. Theoptically active form of the compound of the formula (1) may be producedby using the optically active form of the intermediate for production ofthe formula (I-1) described hereinafter.

An optically active form of each of the compound of the formula (1) andan intermediate for production of this compound is preferably producibleby any of the production processes described as the following productionprocesses 5 to 8. That is, the production processes of optically activeforms of the compound of the formula (1), a pharmaceutically acceptablesalt thereof and an intermediate for production of the compounddescribed as the production process 5 to 8 are also within the scope ofthe present invention.

An intermediate for production of the compound of the formula (1)represented by the formula (4) may be optically resolved by adopting thefollowing production process 5.

Production Process 5

wherein n, R, R¹ and R⁵ are as defined above.

In the production process 5, the alkoxy group for R⁵ is not particularlylimited so long as it is an alkoxy group used as a protective group forcarboxyl group. Specific examples thereof are tert-butoxy group,benzyloxy group, etc.

A racemic modification of the compound of the formula (4) [correspondingto the compound of the formula (1) or an intermediate for production ofthis compound] may be optically resolved by selective oxidization of oneof the optical isomers by treating the racemic modification with anoptically active oxidizing agent in an inert solvent. As the oxidizingagent used here, there are exemplified the Water-modified Sharplessreagent described in Tetrahedron Asymmetry, 8, 13, 2109-2114 (1997),i.e., a mixture of (+)- or (−)-diisopropyl tartrate, titaniumtetraisopropoxide, t-butyl hydroperoxide, a small volume of water andmolecular sieve (4A); and the N-sulfonyloxaziridine reagent described inJ. Org. Chem., 57, 7274 (1992).

A specific example of the optically active oxidizing agent is(+)-(8,8-dichlorocamphorylsulfonyl)oxaziridine. In this case, an S-formof the compound of the formula (1) represented by the formula (4S) isselectively obtainable. On the other hand, an R-form of the compound ofthe formula (1) represented by the formula (4R) is selectivelyobtainable by using (−)-(8,8-dichlorocamphorylsulfonyl)oxaziridine asthe oxidizing agent.

When R is an ethyl group and R⁵ is an NHOH group or an O-tert-butylgroup, the compound may be efficiently optical resolved by treating theracemic modification with 2 equivalents of the optically activeoxidizing agent in methylene chloride. On the other hand, when R is ahydrogen atom and R⁵ is an NHOH group, the compound may be efficientlyoptical resolved by treating the racemic modification with 5 equivalentsof the optically active oxidizing agent in ethyl acetate.

The inert solvent used here is not particularly limited. For example,acetonitrile, methylene chloride and ethyl acetate may be used as theinert solvent. The amount of the inert solvent is not particularlylimited so long as the whole starting material is soluble in the inertsolvent. Although the reaction temperature is not particularly limited,the reaction is usually carried out at 0° C. to 30° C. The reaction timemay be properly controlled by monitoring the disappearance rate of thestarting material and takes usually 1 hour to 10 days.

The compound of the formula (4) may be regenerated by reducing acompound of the formula (4-2R) or (4-2S) obtained by the aboveproduction process 5, with titanium tetraiodide. This reaction isdescribed in Synlett, 2000, 10, 1437-1438.

A compound of the formula (5-5), an optically active form of anintermediate for production of the compound of the formula (1) may beproduced by the following production process 6.

Production Process 6

wherein n, R¹ and R²″ are as defined above; R⁸ is an isopropyl group, anisobutyl group, a phenyl group, a 1-naphthyl group, a 2-naphthyl groupor a benzyl group; and R⁹ is a bromine atom or a hydroxyl group.

In the step 1 in the above reaction scheme, a compound of the formula(5-3) may be obtained by condensing a compound of the formula (5-1) witha compound of the formula (5-2) by a method well known to those skilledin the art. That is, the compound of the formula (5-1) is converted toan acid chloride by treatment with oxalyl chloride and then the acidchloride may be reacted with the compound of the formula (5-2) (acommercial product). The above procedure is described in TetrahedronLett., 38, 3853 (1997).

In the step 2, a compound of the formula (5-4) may be obtained bytreating the compound of the formula (5-3) with an oxidizing agent or abrominating agent in an inert solvent.

That is, when R⁹ is a hydroxyl group in the formula (5-4), Davis reagentmay be used in an inert solvent in the presence of a strong base. Inthis case, R⁸ is preferably a phenyl group. As the strong base usedhere, sodium hexamethyldisilazide is exemplified. As the inert solvent,THF and the like may be used. The amount of the inert solvent is notparticularly limited so long as the whole starting material is solublein the inert solvent. The inert solvent may be used, for example, in avolume of 5 ml to 40 ml per g of the starting material. Although thereaction temperature is not particularly limited, the reaction isusually carried out at −78° C. to 0° C., preferably at −78° C. Thereaction time may be properly controlled by monitoring the disappearanceof the starting material and takes usually 1 hour to 5 hours.

On the other hand, when R⁹ is a bromine atom in the formula (5-4), thecompound of the formula (5-3) may be brominated with N-bromosuccinimideas brominating agent after treatment with dibutylboron triflate anddiisopropylethylamine. In this case, R⁸ is preferably a benzyl group oran isopropyl group.

The inert solvent used here is not particularly limited. For example,methylene chloride may be used as the inert solvent. The amount of theinert solvent is not particularly limited so long as the whole startingmaterial is soluble in the inert solvent. The inert solvent may be used,for example, in a volume of 10 ml to 50 ml per g of the startingmaterial. Although the reaction temperature is not particularly limited,the reaction is usually carried out at −78° C. to 0° C., preferably at−78° C. The reaction time may be properly controlled by monitoring thedisappearance of the starting material and takes usually 1 hour to 5hours.

In the step 3, the compound of the formula (5-5) may be obtained bytreating the compound of the formula (5-4) with a metal alkoxide. Forexample, when R²″ is a methyl group, sodium methoxide, potassiummethoxide or the like may be used in methanol.

When R⁹ is a bromine atom in the compound of the formula (5-4), abenzothiazine compound as intermediate for production of the compound ofthe formula (1) may be obtained according to the following reactionscheme:

wherein n, R¹ and R⁸ are as defined above.

That is, the step 4 and the step 5 may be carried out in the same manneras in the step 1 and step 2 in the above-mentioned production process 2.

An optically active form of the compound of the formula (2) may beproduced by the following production process 7 (see Tetrahedron Lett.,39, 5501 (1998)).

Production Process 7

The optically active form may be produced by treating a compound of theformula (6-1) with an optically active reducing agent such as (+)- or(−)-diisopinocampheylborane chloride (DIP-Cl), and then reacting thetreated compound with an alcohol in the presence of an acid such assulfuric acid to esterify the carboxyl group.

wherein n, R¹ and R² are as defined above.

Specifically, an (S) form of the formula (10S) may be produced bytreating the compound of the formula (6-1) with(+)-diisopinocampheylborane chloride, and an (R) form of the formula(10R) may be produced by treating the compound of the formula (6-1) with(−)-diisopinocampheylborane chloride.

The compound of the formula (10R) or (10S) may be converted to, forexample, an optically active substance of the formula (2R) or (2S) byesterification by a well-known method.

An optically active form of α-hydroxycarboxylic acid as intermediate forproduction of the compound of the formula (2) may be produced by thefollowing production process 8.

Production Process 8

wherein n and R¹ are as defined above.

In the formula (10), formula (10S), formula (10R), formula (11S) andformula (11R) in the above reaction scheme, n is preferably 3 or 4.

A compound of the formula (10) as starting material may be produced by awell-known process or the process described in the working example inthe present specification.

As shown in the above reaction scheme, a (−)-α-tolylethylamine salt of acompound of the formula (10S) may be isolated as a diastereomeric saltby treating the compound of the formula (10) with (−)-α-tolylethylaminein an inert solvent. The compound of the formula (10S) may be producedby treating the diastereomeric salt with an acid by a conventionalmethod.

A (+)-α-tolylethylamine salt of a compound of the formula (10R) may beisolated as a diastereomeric salt by treating the compound of theformula (10) with (+)-α-tolylethylamine in an inert solvent. Thecompound of the formula (10R) may be produced by treating thisdiastereomeric salt with an acid by a conventional method.

Specifically, the optical resolution of the compound of the formula (10)may be carried out by the following steps:

(step 1) a step of dissolving the compound of the formula (10) and anoptically active α-tolylethylamine in an inert solvent,(step 2) a step of precipitating crystals of a diastereomeric saltrepresented by the formula (11S) or (11R), and(step 3) a step of isolating the crystals obtained in (step 2).

The inert solvent used in (step 1) is not particularly limited so longas it can dissolve the compound of the formula (10). Specific examplesthereof are acetone, aqueous acetone, acetonitrile, tetrahydrofuran(THF), 1,4-dioxane, ethyl acetate, toluene, alcohols (e.g. ethanol),etc. Preferable examples thereof are acetone and aqueous acetone. Theinert solvent may be used in a volume of 5 ml to 10 ml per g of thestarting material.

The amount of the optically active α-tolylethylamine used is suitablyabout 0.8 to about 1.5 equivalents, preferably 1 equivalent, perequivalent of the substrate.

The temperature at the formation of the salt by the dissolution of thecompound of the formula (10) and the optically active α-tolylethylamineranges from room temperature to the boiling point of the inert solvent.The reaction is usually carried out at 40° C. to 70° C. For improvingthe optical purity, the temperature is preferably once raised close tothe boiling point of the solvent.

The reaction time may be properly controlled by monitoring thedissolution of the whole starting material and takes usually 0.5 hour to2 hours.

A method for precipitating crystals of the α-tolylethylamine saltrepresented by the formula (11S) or (11R) in (step 2) is notparticularly limited, and a method well known to those skilled in theart may be adopted. For example, the crystals may be precipitated byallowing the solution to stand. In this case, the yield may be improvedby cooling the solution according to need before collecting theprecipitated salt by filtration. In addition, the solvent may beproperly distilled off at atmospheric pressure or under reduced pressureand at room temperature or with heating.

In (step 3), the α-tolylethylamine salt represented by the formula (11S)or (11R) may be obtained in high purity by collecting the formedcrystals by filtration, and if necessary, recrystallizing the crystalsfrom an inert solvent (for example, an alcohol solvent such as methanol,ethanol or 2-propanol; an ether solvent such as diethyl ether; an estersolvent such as ethyl acetate; an aromatic hydrocarbon solvent such astoluene; acetonitrile; or a mixed solvent thereof). Here, the term “highpurity” means a purity of usually 90% ee or more, preferably 95% ee ormore, more preferably 98% ee or more.

If necessary, the α-tolylethylamine salt represented by the formula(11S) or (11R) may be converted to the optically active carboxylic acidcompound of the formula (10S) or (10R), respectively, by the use of anacid such as hydrochloric acid, phosphoric acid, sulfuric acid or thelike. For example, desalting may be conducted by dissolving theα-tolylethylamine salt represented by the formula (11S) or (11R) in anorganic solvent such as ethyl acetate, followed by extraction with a 0.1to 2N aqueous hydrochloric acid solution.

The compound of the formula (10) includes not only a complete racemicmodification (0% ee) consisting of the (+) form and the (−) form in theratio of 1:1 but also a mixture of the (+) form and the (−) form havinga certain degree of optical purity. For example, an optically activeform of the compound of the formula (10) may be produced by the processdescribed in the production process 7 and may be given a higher purityby the method according to the present invention.

The thus obtained optically active form of the compound of the presentinvention and optically active form of the intermediate for productionof the compound of the present invention may be improved in opticalpurity, for example, by a method well known to those skilled in the art.

Specifically, such an optically active substance may be separated bypurification by a fractional recrystallization method comprising theformation of a salt with an optically active base, a chromatographicmethod using an optically active column, or the like. As the aforesaidfractional recrystallization method, there is exemplified a method inwhich a salt with an optically active base (e.g. an organic amine suchas α-phenethylamine, α-tolylethylamine, quinine, quinidine,cinchonidine, cinchonine or strychnine) is formed in an inert solvent(e.g. an alcohol solvent such as methanol, ethanol or 2-propanol; anether solvent such as diethyl ether; an ester solvent such as ethylacetate; an aromatic hydrocarbon solvent such as toluene; acetonitrile;or a mixed solvent thereof). The temperature at the formation of thesalt ranges from room temperature to the boiling point of the solvent.For improving the optical purity, the temperature is preferably onceraised close to the boiling point of the solvent. The yield may beimproved by cooling the reaction solution according to need beforecollecting the precipitated salt by filtration. In general, the amountof the optically active acid or amine used is suitably in a range ofabout 0.5 to about 2.0 equivalents, preferably in a range of about 1equivalent per equivalent of the substrate. If necessary, an opticallyactive salt having a high purity may be obtained by recrystallizing thecrystals from an inert solvent (for example, an alcohol solvent such asmethanol, ethanol or 2-propanol; an ether solvent such as diethyl ether;an ester solvent such as ethyl acetate; an aromatic hydrocarbon solventsuch as toluene; acetonitrile; or a mixed solvent thereof). Ifnecessary, the salt obtained may be treated with an acid or a base by aconventional method to obtain the optically active substance in the freestate.

As the optically active column used in the above-mentionedchromatographic method, optically active columns generally used by thoseskilled in the art may be used. There is, for example, a method in whichthe compound of the formula (1) (including the compounds of the formula(1-8) and the formula (3-3)) is optically resolved by the use of, forexample, CHIRALCEL (trade name) AD-H or CHIRALCEL AS-RH manufactured byDAICEL Chemical Industries Ltd.

Of optically active forms of the compound of the formula (1) of thepresent invention, optically active substances having an S-configurationexhibit higher activity. Specific examples of such compounds are thecompounds of Example 7 and Example 14.

When the compound of the formula (1) and an intermediate for productionof this compound are produced, techniques for protection anddeprotection generally known to those skilled in the art may be used ifnecessary. The techniques for protection and deprotection are describedin detail in the above-mentioned “Green reference”.

When used as a medicine, the compound of the formula (1) or apharmaceutically acceptable salt thereof may be administered orally orparenterally and systemically or locally.

A dosage form in the case of the oral administration includes, forexample, capsules, tablets, powders, cachets and solutions. As to adosage form in the case of the parenteral administration, the compoundor the salt may be administered in the form of, for example, aninjection, transdermal preparation, trans-nasal preparation orintrarectal preparation. As the injection, sterile solutions orsuspensions are exemplified. The transdermal preparation includescreams, ointments, lotions, patch preparations, matrix preparations,etc. The intrarectal preparation includes suppositories, enemas(solution injection), etc. The trans-nasal preparation includesaerosols, nasal drops, etc.

When the compound of the formula (1) is used as a preparation for localadministration, specific examples of the administration route of thecompound are intraarticular administration, transdermal administration,etc.

The compound of the formula (1) or a pharmaceutically acceptable saltthereof may be formulated into a pharmaceutical composition togetherwith pharmaceutically acceptable excipients and additives generally usedby those skilled in the art. The pharmaceutically acceptable excipientsand additives include carriers, binders, flavoring materials, buffers,thickening agents, coloring agents, stabilizers, emulsifying agents,dispersing agents, suspending agents, antiseptics, etc.

The pharmaceutically acceptable carriers include, for example, magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,starch, gelatin, tragacanth, methyl cellulose, sodium carboxymethylcellulose, low-melting wax, and cacao butter. The capsules may beprepared by encapsulating the compound of the present invention togetherwith the pharmaceutically acceptable carrier. The benzothiazin-3-onecompound or pharmaceutically acceptable salt thereof of the presentinvention may be encapsulated together with the pharmaceuticallyacceptable excipient mixed therewith or without the excipient. Thecachets may be prepared in the same manner as above.

As a solution for injection, there are exemplified solutions,suspensions and emulsions, such as aqueous solutions, water-propyleneglycol solutions, and the like. The solution for injection may beprepared in the form of a solution in a poly(ethylene glycol) and/orpropylene glycol which may contain water. A solution suitable for theoral administration may be prepared by adding the compound of thepresent invention to water and adding thereto a coloring agent, aflavoring material, a stabilizer, a sweetener, a solvent, a thickeningagent and the like according to need. A solution suitable for the oraladministration may be prepared also by adding the benzothiazin-3-onecompound or pharmaceutically acceptable salt thereof of the presentinvention to water together with a dispersing agent to increase theviscosity. The thickening agent includes, for example, pharmaceuticallyacceptable natural or synthetic gums, resins, methyl cellulose, sodiumcarboxymethyl cellulose, and well-known suspending agents.

The preparation for local administration includes the above-mentionedsolutions, creams, aerosols, sprays, powders, lotions, ointments, etc.The above-exemplified preparation for local administration may beproduced by mixing the benzothiazin-3-one derivative or salt thereof ofthe present invention with a diluent and a carrier which arepharmaceutically acceptable and conventionally used. Each of theointment and the cream is obtained, for example, by adding a thickeningagent and/or a gelling agent to an aqueous or oily base ingredient,followed by formulation into a pharmaceutical composition. The baseingredient includes, for example, water, liquid paraffins, and vegetableoils (e.g. peanut oil and castor oil). The thickening agent includes,for example, soft paraffins, aluminum stearate, cetostearyl alcohol,propylene glycol, poly(ethylene glycol)s, lanolin, hydrogenated lanolin,and beeswax.

In the case of the lotion, one or more pharmaceutically acceptablestabilizers, suspending agents, emulsifying agents, dispersing agents,thickening agents, coloring agents, flavoring materials and the like maybe added to an aqueous or oily base ingredient.

The powder is obtained by formulating the compound of the formula (1) ora pharmaceutically acceptable salt thereof into the powder together witha pharmaceutically acceptable base ingredient for powder. The baseingredient includes talc, lactose, starch and the like. Drops may beobtained by formulating the compound of the formula (1) or apharmaceutically acceptable salt thereof into the drops together with anaqueous or nonaqueous base ingredient and one or more pharmaceuticallyacceptable dispersing agents, suspending agents, solvents and the like.

If necessary, the preparation for local administration may containantiseptics and bacterial multiplication inhibitors, such as methylhydroxybenzoate, propyl hydroxybenzoate, chlorocresol, benzalkoniumchlorides, etc.

It is also possible to administer through nose a pharmaceuticalcomposition in the form of a solution spray, a powder or drops, whichcontain the benzothiazin-3-one derivative or salt thereof of the presentinvention as an active ingredient.

A compound of the formula (1) in which R is an ethyl group and apharmaceutically acceptable salt thereof are characterized in that theyhave an excellent oral absorbability and act as a prodrug which isconverted to a highly active substance by metabolizing in a living body.That is, as shown in the following scheme:

wherein n and R¹ are as defined above, a compound of the formula (1-8)is metabolized by enzymes in a living body to be converted to ametabolite represented by the formula (3-3). When the compound of theformula (1-8) is orally administered, the compound of the formula (3-3)exhibits an excellent MMP inhibitory activity and has a marked MMPinhibitory activity particularly against MMP-3 and MMP-13, in the livingbody.

That is, the compound of the formula (1-8) or a pharmaceuticallyacceptable salt thereof is preferably orally administered as apreparation for systemic administration or is parenterally administeredas a preparation for local administration.

The compound of the formula (3-3) or a pharmaceutically acceptable saltthereof is preferably parenterally administered.

The dose and the number of administrations of a pharmaceuticalcomposition containing the compound of the formula (1) (the compound ofthe formula (1-8) or the formula (3-3)) or a pharmaceutically acceptablesalt thereof are varied depending on symptom, age, body weight,administration route, etc. When orally administered, the pharmaceuticalcomposition may be administered to an adult in a dose in the range ofusually about 1 to about 1000 mg, preferably about 5 to about 300 mg perday in one portion or several portions. When administered as aninjection, the pharmaceutical composition may be administered to anadult in a dose in the range of usually about 0.1 to about 300 mg,preferably about 1 to about 100 mg per day in one portion or severalportions.

The compound of the formula (1) or a pharmaceutically acceptable saltthereof is usable as a therapeutic or preventive agent for diseases suchas chondrodegenerative diseases such as arthrosis deformans and chronicarticular rheumatism, cancers, inflammatory diseases, COPD (chronicobstructive pulmonary disease), asthma, multiple sclerosis, dermatitis,spondylosis, periodontal disease, wounds, myalgia, ulcers, stenosis,eating disorder, septicemia, etc.

The compound of the formula (1) or a pharmaceutically acceptable saltthereof is preferably useful as, in particular, a therapeutic agent forchondrodegenerative diseases and is very effective as, in particular, atherapeutic agent for arthrosis deformans.

When used as a therapeutic agent for a specific disease, the compound ofthe formula (1) or a pharmaceutically acceptable salt thereof may beused in combination with various therapeutic agents for said disease. Inthe case of chondrodegenerative diseases, the compound of the formula(1) or a pharmaceutically acceptable salt thereof may be used incombination with TNF-α inhibitors (including anti-TNF antibodies),methotrexate, Leflunomide, hydroxychloroquine, d-penicillamine,nonsteroidal anti-inflammatory drugs (e.g. Diclofenac, naproxen,flurbiprofen and ibuprofen), cyclooxygenase 2 inhibitors (e.g. Meloxicamand Celecoxib), salicylic acids (e.g. aspirin), steroids (e.g.corticosteroid), immunosuppressants (e.g. Ciclosporin and Tacrolimus),hyaluronic acids (e.g. Hyalgan and Synvisc), etc. In the case ofcancers, the compound of the formula (1) or a pharmaceuticallyacceptable salt thereof may be used in combination with variousanticancer drugs (e.g. Angiostatin, Adriamycin, cisplatin and Taxol).

The present invention is more concretely illustrated with reference tothe following examples, which are merely for exemplification and shouldnot be construed as limiting the scope of the invention.

In the following examples, the term “room temperature” or “ambienttemperature” means a temperature of 15° C. to 30° C. All of thenonaqueous reactions were carried out under a nitrogen atmosphere. Theterm “concentration under reduced pressure” means that a rotaryevaporator was used.

If necessary, the desired compound obtained may be separated andpurified, for example, by recrystallization, reprecipitation, or aproper combination of methods conventionally adopted for separation andpurification of an organic compound [for example, an adsorption columnchromatography method using a support such as silica gel, alumina, ormagnesium-silica gel type Florisil; a method using a syntheticadsorbent, such as partition column chromatography using a support suchas Sephadex LH-20 (mfd. by Pharmacia AB), Amberlite XAD-11 (mfd. by Rohm& Haas Co.) or Diaion HP-20 (mfd. by Mitsubishi Chemical Company); amethod using ion-exchange chromatography; and a normal-phase orreversed-phase column chromatography (preferably high performance liquidchromatography) using silica gel or lower-alkylated silica gel] followedby elution with a suitable eluent.

In the following description, the NMR data are reported in ppm (δ) andare based on comparison with lock signals of deuterium from a solventfor sample. Commercial reagents were used without further purification.CDCl₃ denotes deuterated chloroform and DMSO-d6 denotes deuterateddimethyl sulfoxide. As these reagents, commercial reagents were usedwithout further purification. Abbreviations used in the NMR data are asfollows:

s: singlet

d: doublet

t: triplet

dd: doublet doublet

m: multiplet

br: broad

brs: broad singlet

Example 1 Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Step A

Under ice-cooling, sodium hydride (4.65 g, content 60%) was added insmall portions to a THF solution (300 ml) containing(2E)-3-(4-methoxyphenyl)acrylaldehyde (10 g) synthesized by the processdescribed in Reference Example 1 and ethyl2-(diethoxyphosphoryl)-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(21.7 g, synthesized according to the process disclosed in WO00/63197).The resulting mixture was slowly warmed up to room temperature andstirred overnight. The same aldehyde as above (1.5 g) was added theretoand stirred for another 2 hours. The resulting mixture was concentratedunder reduced pressure, and ethyl acetate (30 ml), hexane (100 ml), a 1Naqueous hydrochloric acid solution (50 ml) and water (600 ml) were addedto the residue, followed by stirring at room temperature for 6 hours.The solid was collected by filtration and dried under reduced pressure.Ethyl2-[3-(4-methoxyphenyl)prop-2-en-1-ylidene]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(22.43 g) was obtained as a yellow solid.

¹H-NMR (DMSO-d6) δ 1.33 (t, J=7.1 Hz, 3H), 3.76+3.80 (s, 3H), 4.30 (q,J=7.1 Hz, 2H), 6.92-7.08 (m, 4H), 7.35-7.45 (m, 2H), 7.52-7.58 (m, 3H),7.66 (d, J=1.7 Hz, 1H), 10.90+10.95 (brs, 1H).

Step B

Under ice-cooling, sodium hydride (1.68 g, content 60%) was added insmall portions to ethyl2-[3-(4-methoxyphenyl)prop-2-en-1-ylidene]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(12.3 g) and DMF (150 ml). After 10 minutes, the resulting mixture wasstirred at room temperature. After 4 hours, tert-butyl bromoacetate (5.7ml) was added dropwise thereto under ice-cooling. After 1 hour, theresulting mixture was poured into an aqueous sodium chloride solutionand extracted with ethyl acetate. The oil layer was dehydrated overanhydrous sodium sulfate and concentrated under reduced pressure. Theresidue was purified by a silica gel chromatography (eluent:hexane/ethyl acetate=2/1) to obtain a yellow oil (14.45 g). To thisyellow oil were added 1,4-dioxane (200 ml), methanol (200 ml), aceticacid (10 ml) and 10%-palladium-carbon (10 g, containing 50% water), andthe resulting mixture was stirred under a hydrogen atmosphere at roomtemperature and atmospheric pressure. After 12 hours, the solid wasfiltered off and washed with ethyl acetate and the filtrate wasconcentrated under reduced pressure. The residue was purified by asilica gel chromatography (hexane/ethyl acetate=3/1) to obtain ethyl4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(13.16 g) as a yellow oil.

¹H-NMR (CDCl₃) δ 1.38 (t, J=7.1 Hz, 3H), 1.49 (s, 9H), 1.60 (m, 1H),1.71 (m, 1H), 1.75-1.98 (m, 2H), 2.54 (m, 2H), 3.48 (m, 1H), 3.76 (s,3H), 4.32-4.41 (m, 3H), 4.82 (m, 1H), 6.76-6.80 (m, 2H), 7.02-7.06 (m,2H), 7.40 (m, 1H), 7.50 (m, 1H), 7.70 (m, 1H).

Step C

Under ice-cooling, a boron trifluoride-diethyl ether complex (26.6 ml)was added dropwise to a solution of ethyl4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(13.16 g) and dimethyl sulfide (26.3 ml) in dichloromethane (250 ml).The resulting mixture was slowly warmed up to room temperature and thenstirred overnight. The mixture was poured into a 1N aqueous hydrochloricacid solution and extracted with chloroform. The oil layer was washedtwice with a 1N aqueous hydrochloric acid solution, dehydrated overanhydrous sodium sulfate and then concentrated under reduced pressure.{6-(Ethoxycarbonyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid (10.64 g) was obtained as a yellow oil.

¹H-NMR (CDCl₃) δ 1.39 (t, J=7.2 Hz, 3H), 1.60 (m, 1H), 1.70 (m, 1H),1.75-1.93 (m, 2H), 2.52 (m, 2H), 3.50 (m, 1H), 3.77 (s, 3H), 4.38 (q,J=7.2 Hz, 2H), 4.59 (m, 1H), 4.92 (m, 1H), 6.76-6.80 (m, 2H), 7.00-7.04(m, 2H), 7.41 (d, J=8.1 Hz, 1H), 7.55 (m, 1H), 7.71 (m, 1H).

Step D

At −15° C., isopropyl chloroformate (2.84 ml) was added dropwise to asolution of{6-(ethoxycarbonyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid (10.64 g) and N-methylmorpholine (3.2 ml) in tetrahydrofuran (200ml). After the dropwise addition of the whole isopropyl chloroformate,the resulting mixture was stirred for 25 minutes and thenO-(trimethylsilyl)hydroxylamine (3.52 ml) was added dropwise thereto.After 3 hours, the reaction mixture was poured into a 0.5N aqueoushydrochloric acid solution and extracted with ethyl acetate. The oillayer was washed with a saturated aqueous sodium chloride solution,dehydrated over anhydrous sodium sulfate and then concentrated underreduced pressure. The residue was purified by a silica gelchromatography (hexane/ethyl acetate=2/3 to 1/3). To the resultingyellow oil were added toluene and hexane to effect crystallization. Thesolid obtained was collected by filtration and concentrated underreduced pressure. Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(8.24 g) was obtained as a yellow solid.

¹H-NMR (CDCl₃) δ 1.40 (t, J=7.2 Hz, 3H), 1.59 (m, 1H), 1.67 (m, 1H),1.77-1.93 (m, 2H), 2.54 (m, 2H), 3.47 (m, 1H), 3.77 (s, 3H), 4.38 (q,J=7.2 Hz, 2H), 4.51 (d, J=16.0 Hz, 1H), 4.68 (d, J=16.0 Hz, 1H), 6.80(m, 2H), 7.04 (m, 2H), 7.41 (d, J=8.0 Hz, 1H), 7.52 (br, 1H), 7.73 (m,1H), 7.98 (br, 1H), 9.16 (br, 1H).

Example 2 Ethyl2-[3-(4-chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl2-[3-(4-chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas obtained by the same process as in Example 1.

¹H-NMR (CDCl₃) δ: 1.40 (t, J=7.2 Hz, 3H), 1.60 (m, 2H), 1.85 (m, 2H),2.56 (m, 2H), 3.47 (m, 1H), 4.38 (q, J=7.2 Hz, 2H), 4.52 (d, J=16.0 Hz,1H), 4.68 (d, J=16.0 Hz, 1H), 7.05 (m, 2H), 7.21 (m, 2H), 7.40 (d, J=8.0Hz, 1H), 7.60-7.76 (m, 2H), 7.96 (br, 1H), 8.63+9.28 (br, 1H).

Example 3 Ethyl2-[3-(4-fluorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl2-[3-(4-fluorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas obtained by the same process as in Example 1.

¹H-NMR (CDCl₃) δ: 1.40 (t, J=7.2 Hz, 3H), 1.56 (m, 1H), 1.66 (m, 1H),1.85 (m, 2H), 2.57 (m, 2H), 3.47 (m, 1H), 4.39 (q, J=7.2 Hz, 2H), 4.52(d, J=15.6 Hz, 1H), 4.69 (d, J=15.6 Hz, 1H), 6.93 (m, 2H), 7.07 (m, 2H),7.41 (d, J=8.0 Hz, 1H), 7.50 (br, 1H), 7.73 (m, 1H), 7.98 (br, 1H), 9.27(br, 1H).

Example 4 Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethoxy)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethoxy)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas obtained by the same process as in Example 1.

¹H-NMR (CDCl₃) δ: 1.40 (t, J=7.2 Hz, 3H), 1.61 (m, 1H), 1.69 (m, 1H),1.84 (m, 2H), 2.60 (m, 2H), 3.49 (m, 1H), 4.39 (t, J=7.2 Hz, 2H), 4.52(d, J=16.4 Hz, 1H), 4.70 (d, J=16.4 Hz, 1H), 7.08-7.16 (m, 4H), 7.41 (d,J=8.0 Hz, 2H), 7.73 (m, 2H), 7.99 (br, 1H), 9.21 (br, 1H).

Example 5

Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethyl)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethyl)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas obtained by the same process as in Example 1.

¹H-NMR (DMSO-d6). δ: 1.31 (t, J=7.2 Hz, 3H), 1.45 (m, 1H), 1.71 (m, 3H),2.65 (m, 2H), 3.76 (m, 1H), 4.30 (q, J=7.2 Hz, 2H), 4.37 (d, J=8.4 Hz,1H), 4.58 (d, J=8.4 Hz, 1H), 7.38 (m, 2H), 7.52-7.61 (m, 5H), 9.04+9.44(s, 1H), 10.39+10.84 (s, 1H).

Example 6 Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas obtained by the same process as in Example 1.

¹H-NMR (DMSO-d6) δ: 1.31 (t, J=7.2 Hz, 3H), 1.35-1.54 (m, 5H), 1.73 (m,1H), 2.44 (m, 2H), 3.63-3.72 (m, 4H), 4.31 (q, J=7.2 Hz, 2H), 4.41 (d,J=16.8 Hz, 1H), 4.55 (d, J=16.8 Hz, 1H), 6.80 (m, 2H), 7.05 (m, 2H),7.55 (d, J=8.4 Hz, 1H), 7.60-7.64 (m, 2H), 9.04+9.43 (s, 1H),10.38+10.83 (s, 1H).

Example 7 (−)-Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

In THF (40 ml) was dissolved{(2S)-6-(ethoxycarbonyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid (the compound of Reference Example 11) (2.06 g), and isobutylchloroformate (0.72 ml) and N-methylmorpholine (0.51 ml) were addedthereto at −20° C. and stirred at −10 to −20° C. for 30 minutes. AfterO-(trimethylsilyl)hydroxylamine(0.87 ml) was added thereto, theresulting mixture was warmed up to room temperature and stirred for 1hour. The reaction mixture was poured into a saturated aqueous sodiumhydrogencabonate solution and extracted with ethyl acetate, and theorganic layer was washed with a saturated aqueous ammonium chloridesolution and a saturated aqueous sodium chloride solution and then driedover anhydrous sodium sulfate. The drying agent was removed byfiltration and the solvent was distilled off under reduced pressure. Theresidue was recrystallized from a mixed solvent of ethyl acetate anddiisopropyl ether to obtain (−)-ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(1.69 g, 99.9% e.e.). The optical purity analysis conditions are asfollows. [Column: AD-H(CHIRALCEL, DAICEL Chemical Industries Ltd.);detecting wavelength (UV): 254 nm; flow rate: 1.0 ml/min; mobile phase:n-hexane/isopropyl alcohol/TFA=80/20/0.1]

Melting point: 143.5-144.5° C.

[α]_(D) ²⁰=−85.3° (c: 1.0, CHCl₃)

¹H-NMR (CDCl₃) δ: 1.40 (t, J=7.2 Hz, 3H), 1.59 (m, 1H), 1.67 (m, 1H),1.77-1.93 (m, 2H), 2.54 (m, 2H), 3.47 (m, 1H), 3.77 (s, 3H), 4.38 (q,J=7.2 Hz, 2H), 4.51 (d, J=16.0 Hz, 1H), 4.68 (d, J=16.0 Hz, 1H), 6.80(m, 2H), 7.04 (m, 2H), 7.41 (d, J=8.0 Hz, 1H), 7.52 (br, 1H), 7.73 (m,1H), 7.98 (br, 1H), 9.16 (br, 1H).

Example 84-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

To the compound of Example 1 (0.51 g) were added THF (10 ml) and water(10 ml). After the resulting mixture was ice-cooled, a 0.5N aqueouslithium hydroxide solution (4.4 ml) was slowly added dropwise thereto.The resulting mixture was slowly warmed up to room temperature andstirred overnight. Ice-cooled 1N aqueous hydrochloric acid solution andethyl acetate were added thereto to effect extraction. The oil layer waswashed twice with a 1N aqueous hydrochloric acid solution, dried overanhydrous sodium sulfate and then concentrated under reduced pressure.Chloroform was added to the residue, and after standing for 4 days, thesolid precipitated was collected by filtration and dried under reducedpressure.4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (325 mg) was obtained as a white solid.

¹H-NMR (DMSO-d6) δ 1.43 (m, 1H), 1.66 (m, 3H), 2.45 (m, 2H), 3.69 (s,3H), 4.38 (d, J=16.8 Hz, 1H), 4.54 (d, J=16.8 Hz, 1H), 6.80 (m, 2H),7.05 (m, 2H), 7.51 (m, 1H), 7.58-7.60 (m, 2H), 9.02+9.43 (s, 1H),10.36+10.81 (s, 1H), 13.20 (brs, 1H).

Example 92-[3-(4-Chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

2-[3-(4-Chlorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid was obtained by a process similar to the process described inExample 8.

¹H-NMR (DMSO-d6) δ 1.45 (m, 1H), 1.68 (m, 3H), 2.54 (m, 2H), 3.73 (m,1H), 4.38 (d, J=16.4 Hz, 2H), 4.56 (d, J=16.4 Hz, 1H), 7.18 (m, 2H),7.29 (m, 2H), 7.51 (d, J=8.0 Hz, 1H), 7.59-7.61 (m, 2H), 9.03+9.43 (s,1H), 10.37+10.82 (s, 1H), 13.17 (br, 1H).

Example 102-[3-(4-Fluorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

2-[3-(4-Fluorophenyl)propyl]-4-[2-(hydroxyamino)-2-oxoethyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid was obtained by a process similar to the process described inExample 8.

¹H-NMR (DMSO-d6) δ 1.45 (m, 1H), 1.67 (m, 3H), 2.54 (m, 2H), 3.73 (m,1H), 4.38 (d, J=16.8 Hz, 2H), 4.55 (d, J=16.8 Hz, 1H), 7.06 (m, 2H),7.18 (m, 2H), 7.51 (d, J=8.0 Hz, 1H), 7.59 (m, 2H), 9.03+9.43 (s, 1H),10.37+10.82 (s, 1H), 13.17 (br, 1H).

Example 114-[2-(Hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethoxy)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

4-[2-(Hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethoxy)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid was obtained by a process similar to the process described inExample 8.

¹H-NMR (DMSO-d6) δ 1.47 (m, 1H), 1.70 (m, 3H), 2.59 (m, 2H), 3.75 (m,1H), 4.39 (d, J=16.8 Hz, 1H), 4.56 (d, J=16.8 Hz, 1H), 7.22 (m, 2H),7.28 (m, 2H), 7.51 (m, 1H), 7.59 (m, 2H), 9.63+9.43 (s, 1H), 10.37+10.82(s, 1H), 13.12 (br, 1H).

Example 124-[2-(Hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethyl)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

4-[2-(Hydroxyamino)-2-oxoethyl]-3-oxo-2-{3-[4-(trifluoromethyl)phenyl]propyl}-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid was obtained by a process similar to the process described inExample 8.

¹H-NMR (DMSO-d6) δ 1.47 (m, 1H), 1.72 (m, 3H), 2.64 (m, 2H), 3.76 (m,1H), 4.38 (d, J=16.8 Hz, 1H), 4.56 (d, J=16.8 Hz, 1H), 7.49 (m, 2H),7.51 (m, 1H), 7.58-7.61 (m, 3H), 9.03+9.44 (s, 1H), 10.37+10.82 (s, 1H),13.13 (br, 1H).

Example 134-[2-(Hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

4-[2-(Hydroxyamino)-2-oxoethyl]-2-[4-(4-methoxyphenyl)butyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid was obtained by a process similar to the process described inExample 8.

¹H-NMR (DMSO-d6) δ 1.35-1.56 (m, 5H), 1.75 (m, 1H), 2.45 (m, 2H), 3.68(m, 1H), 3.70 (s, 3H), 4.41 (d, J=16.8 Hz, 1H), 4.53 (d, J=16.8 Hz, 1H),6.80 (m, 2H), 7.05 (m, 2H), 7.52 (d, J=8.0 Hz, 1H), 7.58-7.62 (m, 2H),9.03+9.43 (s, 1H), 10.36+10.81 (s, 1H), 13.06 (br, 1H).

Example 14(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

The compound of Example 7 (0.51 g) was added to a solution prepared byadding N-methylglucamine to a 0.1M aqueous sodium dihydrogenphosphatesolution to adjust the pH to 8.0, and the resulting mixture was stirredat 40° C. Porcine liver esterase (250 mg) was added thereto and theresulting mixture was stirred at 40° C. for 8 hours and then at roomtemperature for 4 days. After the reaction mixture was filtered,potassium hydrogensulfate (13.0 g) was added to the filtrate, followedby extraction with ethyl acetate. The oil layer was washed with a 5%aqueous potassium hydrogensulfate solution and a saturated aqueoussodium chloride solution, dehydrated over anhydrous sodium sulfate andthen concentrated under reduced pressure. To the residue were added THFand diisopropyl ether to effect crystallization, and the solid wascollected by filtration and dried under reduced pressure.(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (376 mg, 99% e.e.) was obtained as a white solid. The opticalpurity analysis conditions are as follows. [Column: AS-RH (Chiralcel,DAICEL Chemical Industries Ltd.); detecting wavelength (UV): 254 nm;flow rate: 1.0 ml/min; mobile phase: acetonitrile/0.2M phosphate buffer(pH 2)=25/75]

[α]D¹⁸=−92.1° (c:0.1,EtOH)

¹H-NMR (DMSO-d6) δ 1.43 (m, 1H), 1.66 (m, 3H), 2.45 (m, 2H), 3.69 (s,3H), 4.38 (d, J=16.8 Hz, 1H), 4.54 (d, J=16.8 Hz, 1H), 6.80 (m, 2H),7.05 (m, 2H), 7.51 (m, 1H), 7.58-7.60 (m, 2H), 9.02+9.43 (s, 1H),10.36+10.81 (s, 1H), 13.20 (brs, 1H).

Example 15(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

In THF (200 mL) was dissolved 4.59 g (10.0 mmol) of the compound ofExample 7 (HPLC purity 99% and optical purity 100% ee), and 2N—KOH (12.5mL, 25.0 mmol) was added thereto with stirring at −10° C. (internaltemperature) and stirred at the same temperature for 5 hours. Thereaction mixture was poured into a 0.1N-aqueous hydrochloric acidsolution (500 mL) cooled at 0° C. and extracted twice with ethyl acetate(400+100 mL). The organic layer was collected, washed with water and asaturated aqueous sodium chloride solution, dried over magnesium sulfateand then concentrated with an evaporator to obtain 4.65 g of(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (HPLC purity 97% and optical purity 94% ee) as a light-yellowsolid.

Example 16(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

In THF (1 L) was dissolved 46.0 g (100 mmol) of the compound of Example7 (HPLC purity 99% and optical purity 100% ee), and 2N—NaOH (125 mL, 250mmol) was added thereto with stirring at −10° C. (internal temperature)and stirred at the same temperature for 3 hours. The reaction mixturewas poured into a 0.2N-aqueous hydrochloric acid solution (2 L) cooledat 0° C. and extracted twice with ethyl acetate (1.5+0.5 L). The organiclayer was collected, washed with water and a saturated aqueous sodiumchloride solution, dried over magnesium sulfate and then concentratedwith an evaporator to obtain 50.3 g of a light-yellow solid (HPLC purity97% and optical purity 94% ee). Chloroform (500 ml) was added to thesolid and the resulting mixture was heated under reflux on an oil bath.When the solid dissolved, the reactor was taken off the oil bath, andseed crystals (a earpick-ful) of the desired compound were added to thereaction solution and the resulting mixture was heated under reflux onthe oil bath for 30 minutes to obtain a slurry. Then, the slurry wasstirred overnight at room temperature. The slightly brown crystalsprecipitated were collected by filtration and dried under reducedpressure at 50° C. to obtain 35.7 g of the desired compound (HPLC purity99% and optical purity 98% ee) as a crude product. The crude product wasdissolved in ethanol (200 mL) and hexane (200 mL) was added thereto withstirring at room temperature. Then, hexane (200 mL) was added dropwisethereto while adding seed crystals (0.26 g, 0.60 mmol) of the desiredcompound in several portions. The resulting mixture was stirredovernight at room temperature. The crystals precipitated were collectedby filtration and dried under reduced pressure at 50° C. to obtain 27.0g of(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (HPLC purity 99% and optical purity 99% ee or more) as whitecrystals.

Example 17(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

In THF (100 mL) was dissolved 9.19 g (20.0 mmol) of the compound ofExample 7 (HPLC purity 99% and optical purity 100% ee), and 4N—NaOH(12.0 mL, 48.0 mmol) was added thereto with stirring at −10° C.(internal temperature) and stirred at the same temperature for 4 hours.The reaction mixture was poured into a 0.2N-aqueous hydrochloric acidsolution (400 mL) cooled at 0° C. and extracted twice with ethyl acetate(300+100 mL). The organic layer was collected, washed with water and asaturated aqueous sodium chloride solution, dried over magnesium sulfateand then concentrated with an evaporator to obtain 9.27 g of alight-yellow solid (HPLC purity 94% and optical purity 96% ee). Thissolid was dissolved in ethanol (50 mL) and pentane (50 mL) was addedthereto with stirring at room temperature. Then, pentane (50 mL) wasadded dropwise thereto while adding seed crystals (0.62 g, 1.44 mmol) ofthe desired compound in several portions. The resulting mixture wasstirred overnight at room temperature. The crystals precipitated werecollected by filtration and dried under reduced pressure at 50° C. toobtain 4.75 g of(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (HPLC purity 99% and optical purity 99% ee or more) as whitecrystals.

Reference Example 1 (2E)-3-(4-Methoxyphenyl)acryl-aldehyde

A solution of diisobutylaluminum hydride in hexane (0.95 molarconcentration, 200 ml) was added dropwise to a solution of methyl(2E)-3-(4-methoxyphenyl)acrylate (18 g) in THF (150 ml) underice-cooling. The resulting mixture was slowly warmed up to roomtemperature and then poured into an ice-cooled aqueous hydrochloric acidsolution. After extraction with ethyl acetate, the oil layer was washedwith a 1N aqueous hydrochloric acid solution and then a saturatedaqueous sodium chloride solution, dehydrated over anhydrous sodiumsulfate, and concentrated under reduced pressure. A white solid (13.67g) was obtained.

Subsequently, manganese dioxide (38.4 g) was added to a solution of thewhite solid (7.67 g) in chloroform (200 ml), and the resulting mixturewas stirred overnight at room temperature. The solid was collected byfiltration through Celite and washed with chloroform and then thefiltrate was concentrated under reduced pressure. The remaining whitesolid (6 g) was subjected to the same procedure as above. Theconcentrates thus obtained were combined to obtain(2E)-3-(4-methoxyphenyl)acrylaldehyde (13.7 g) as a yellow solid.

¹H-NMR (CDCl₃) δ 3.86 (s, 3H), 6.61 (dd, J=15.8, 7.8 Hz, 1H), 6.95 (d,J=8.6 Hz, 2H), 7.43 (d, J=15.9 Hz, 1H), 7.53 (d, J=8.6 Hz, 2H), 9.65 (d,J=7.7 Hz, 1H).

Reference Example 2 (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoic acid

Step F

Methylene chloride (300 ml) was added to aluminum chloride (185.6 g) andanisole (100 ml) was added dropwise thereto at 0° C. Succinic anhydride(100 g) was added thereto in 5 portions and the resulting mixture waswarmed up to room temperature and stirred for 3 hours. The reactionsolution was added to a 4N aqueous hydrochloric acid solution (2 L) andethyl acetate (1 L) under ice-cooling, and the crystals precipitatedwere collected by filtration and dried to obtain4-(4-methoxyphenyl)-4-oxobutanoic acid (160 g) as a white solid.

¹H-NMR (DMSO-d6) δ 2.56 (t, J=6.3 Hz, 2H), 3.18 (t, J=6.3 Hz, 2H), 3.84(s, 3H), 7.02-7.07 (m, 2H), 7.94-7.98 (m, 2H), 12.14 (brs, 1H).

Step G

After 4-(4-methoxyphenyl)-4-oxobutanoic acid (40 g) was added to (notcompletely dissolved in) a mixed solvent of acetic acid (100 ml) and THF(100 ml), 10% palladium-carbon (50%-wet) (4 g) was added thereto and theresulting mixture was stirred for 9 hours under a hydrogen atmosphere(0.4 MPa). The catalyst was removed by filtration through Celite andtoluene was added to the residue. The solvent was distilled off underreduced pressure to obtain 4-(4-methoxy-phenyl)butanoic acidquantitatively.

¹H-NMR (CDCl₃) δ 1.89 (m, 2H), 2.32 (t, J=7.3 Hz, 2H), 2.58 (t, J=7.4Hz, 2H), 3.73 (s, 3H), 6.78-6.82 (m, 2H), 7.03-7.08 (m, 2H), 10.96 (brs,1H).

Step H

After 4-(4-methoxyphenyl)butanoic acid (200 g) and then concentratedsulfuric acid (4 ml) were added to ethanol (400 ml), the resultingmixture was heated under reflux for 1 hour. About one-half of thesolvent was distilled off under reduced pressure, and the residualreaction solution was poured into a saturated aqueous sodiumhydrogencarbonate solution and extracted with ethyl acetate (1 L). Theorganic layer was washed with a saturated aqueous sodium chloridesolution and dried over anhydrous magnesium sulfate. The solvent wasdistilled off under reduced pressure to obtain ethyl4-(4-methoxyphenyl)butanoate quantitatively.

¹H-NMR (CDCl₃) δ 1.24 (t, J=7.1 Hz, 3H), 1.92 (m, 2H), 2.30 (t, J=7.5Hz, 2H), 2.59 (t, J=7.4 Hz, 2H), 3.78 (s, 3H), 4.13 (q, J=7.1 Hz, 2H),6.80-6.84 (m, 2H), 7.07-7.12 (m, 2H).

Step I

A previously prepared solution of NaOEt (184 g) in ethanol (940 ml) wasadded dropwise to ethyl 4-(4-methoxyphenyl)butanoate (200.1 g) anddiethyl oxalate (407 ml) under ice-cooling. After stirring at 50° C. for10 hours, the resulting solution was poured into an ice-cooled 3Naqueous hydrochloric acid solution (1.8 L). After extraction with ethylacetate (600 ml×3 times), the extract solution was distilled underreduced pressure to remove the solvent, and the brown organic layer thusseparated was collected. The crystals precipitated in the organic layerwere collected by filtration and washed with hexane/ethyl acetate=10/2.The washings and the organic layer freed from the crystals were combinedand the solvent was distilled off. The residue was used in thesubsequent step.

¹H-NMR (CDCl₃) δ 1.25 (t, J=7.1 Hz, 3H), 1.36 (t, J=7.1 Hz, 3H),2.16-2.28 (m, 2H), 2.59-2.67 (m, 2H), 3.89 (s, 3H), 4.00 (t, J=6.9 Hz,1H), 4.19 (q, J=7.1 Hz, 2H), 4.32 (q, J=7.1 Hz, 2H), 6.80-6.84 (m, 2H),7.07-7.12 (m, 2H).

Step J

The product described above (403 g) was dissolved in 1,4-dioxane (675ml), followed by adding thereto a 3N aqueous hydrochloric acid solution(1100 ml), and the resulting mixture was heated under reflux for 23hours. The reaction solution was cooled to room temperature and allowedto stand. The organic layer thus separated and an extract solutionobtained by extracting the aqueous layer with ethyl acetate (500 ml)were collected, and the solvent was distilled off under reducedpressure. The residue was adjusted to pH 9 with a 2N aqueous sodiumhydroxide solution and the solid precipitated was collected byfiltration and washed with water. After a 3N aqueous hydrochloric acidsolution was added to the recovered solid to adjust the pH to 2, theprecipitate was collected by filtration, washed with water and thendried to obtain 5-(4-methoxyphenyl)-2-oxopentanoic acid (144.8 g) as abrown solid.

¹H-NMR (CDCl₃) δ 1.96 (m, 2H), 2.62 (t, J=7.4 Hz, 2H), 2.93 (t, J=7.2Hz, 2H), 3.79 (s, 3H), 6.82-6.86 (m, 2H), 7.05-7.12 (m, 2H), 8.02 (brs,1H).

Reference Example 3 2-Hydroxy-5-(4-methoxy-phenyl)pentanoic acid

Sodium hydroxide (24.0 g) and water (450 ml) were added to5-(4-methoxyphenyl)-2-oxopentanoic acid (66.6 g) (the compound ofReference Example 2), and the resulting mixture was ice-cooled. When tothis slurry was added sodium tetrahydroborate (3.99 g) in portions, thereaction mixture once became clear. After the reaction mixture wasstirred for 2 hours, a 3N aqueous hydrochloric acid solution (300 ml)was added thereto, followed by extraction with ethyl acetate (300ml×twice). The organic layer was washed with water (100 ml×three times)and dried over anhydrous sodium sulfate. The solvent was distilled offunder reduced pressure to obtain 2-hydroxy-5-(4-methoxyphenyl)pentanoicacid (63.4 g) as a crude product.

¹H-NMR (CDCl₃) δ: 1.67-1.80 (m, 3H), 1.83-1.90 (m, 1H), 2.62 (m, 2H),3.79 (s, 3H), 4.28 (m, 1H), 6.82 (m, 2H), 7.10 (m, 2H).

Reference Example 4 (2R)-2-Hydroxy-5-(4-methoxyphenyl)pentanoic acid

The compound of Reference Example 3(2-hydroxy-5-(4-methoxyphenyl)pentanoic acid) (1.0 g) was dissolved inacetone (10 ml), followed by adding thereto (+)-tolylethylamine (0.6 g),and the resulting mixture was heated under reflux to dissolvecompletely. Crystals were precipitated at room temperature and collectedby filtration as crude crystals. The crude crystals obtained wereresuspended in acetone (10 ml) and the resulting suspension was refluxedand then slowly cooled. The crystals thus obtained were collected byfiltration to obtain (+)-tolylethylamine salt (0.59 g, 98% e.e.) of(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoic acid. A 1N aqueoushydrochloric acid solution (20 ml) was added to the white crystalsobtained and the resulting mixture was stirred at room temperature. Theprecipitate was collected by filtration and dried to obtain(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoic acid (0.36 g) having anoptical purity of 98% e.e., as a white solid. The optical purityanalysis conditions are as follows. [Optical purity analysis conditions:column=OJ-H (Chiralcel, DAICEL Chemical Industries Ltd.); detectingwavelength (UV)=276 nm; flow rate: 1.0 ml/min; mobilephase=n-hexane/ethanol/TFA (90/10/0.2)]

¹H-NMR (CDCl₃) δ: 1.66-1.92 (m, 4H), 2.61 (m, 1H), 3.78 (s, 3H), 4.26(m, 1H), 6.80-6.85 (m, 2H), 7.03-7.12 (m, 2H).

Reference Example 5 4-Nitrobenzyl(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoate

The compound of Reference Example 4 (4.21 g, 98% e.e.) was dissolved inDMF (40 ml), and p-nitrobenzyl bromide (4.06 g) and triethylamine (3.2ml) were added thereto under ice-cooling. The resulting mixture wasstirred for 5 minutes, warmed up to room temperature and then stirredfor 2 hours. The reaction mixture was poured into a saturated aqueousammonium chloride solution and extracted with ethyl acetate, and theextract solution was washed with a saturated aqueous sodium chloridesolution and dried over anhydrous sodium sulfate. The drying agent wasremoved, followed by concentration under reduced pressure, and theresidue was purified by a silica gel column chromatography (hexane/ethylacetate=2/1) to obtain 4-nitrobenzyl(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoate (5.43 g, 98% e.e.). Theoptical purity analysis conditions are as follows. [Optical purityanalysis conditions: column=AD-RH (Chiralcel, DAICEL Chemical IndustriesLtd.); detecting wavelength (UV)=254 nm; flow rate: 1.0 ml/min; mobilephase=acetonitrile/water (50/50)]

¹H-NMR (CDCl₃) δ: 1.60-1.90 (m, 4H), 2.56 (m, 2H), 2.68 (d, J=5.8 Hz,1H), 3.79 (s, 3H), 4.29 (m, 1H), 5.25 (d, J=13.2 Hz, 1H), 5.30 (d,J=13.2 Hz, 1H), 6.79-6.83 (m, 2H), 7.04-7.09 (m, 2H), 7.47 (d, J=8.8 Hz,2H), 8.19-8.24 (m, 2H).

Reference Example 6 Ethyl 3-bromo-4-mercaptobenzoate

Step L

3-Bromo-4-fluorobenzonitrile (100 g) was dissolved in dimethylformamide(DMF) (500 ml), and sodium sulfide nonahydrate (132 g) was added theretoat 0° C. and then stirred overnight at room temperature. The reactionmixture was poured to ice water (1 L) and the insoluble material wasfiltered off. The filtrate was added to a 1N aqueous hydrochloric acidsolution (700 ml) under ice-cooling and the precipitate was collected byfiltration. The crystals thus obtained were washed withhexane/diisopropyl ether and water and then dried to obtain3-bromo-4-mercaptobenzonitrile (95.0 g) as a light-yellow solid.

¹H-NMR (400M, DMSO-d6) δ 7.72 (s, 2H), 8.14 (s, 1H).

Step M

3-Bromo-4-mercaptobenzonitrile (10 g) was dissolved in toluene (50 ml)and chloroform (80 ml), followed by adding thereto ethanol (3.0 ml), andthe resulting mixture was cooled to −10° C. Hydrochloric acid gas wasbubbled into the mixture through a bubbler for 10 minutes and theresulting mixture was stirred at the same temperature for 30 minutes.The reaction mixture was allowed to stand in a refrigerator for 60 hoursand then the completion of the reaction was confirmed by HPLC(ODS-A212).Dry nitrogen was bubbled into the reaction solution through a bubblerfor 20 minutes and the hydrochloric acid gas was distilled off. Theprecipitate was collected by filtration, washed with toluene/chloroformand then dried to obtain ethyl 3-bromo-4-mercaptobenzene-carboximidate(13.6 g) as a light-yellow solid.

¹H-NMR (400M, DMSO-d6) δ 1.47 (t, J=7.0 Hz, 3H), 4.59 (q, J=7.0 Hz, 2H),7.83-7.90 (m, 2H), 7.92-7.88 (m, 2H), 8.32 (s, 2H).

Step N

Ethyl 3-bromo-4-mercaptobenzenecarboximidate (3.00 g) was dissolved inethanol (100 ml), and water (10 ml) and then concentrated sulfuric acid(10 ml) were added dropwise thereto at 0° C. and stirred overnight atroom temperature. Zinc (1 g) was added to the reaction system and theresulting mixture was stirred at room temperature for 2 hours to inducethe production of a monomer. After the zinc powder was removed byfiltration through Celite, the ethanol was distilled off under reducedpressure, followed by extraction with ethyl acetate, and the organiclayer was washed with water (×4). The organic layer was dried overanhydrous sodium sulfate and then concentrated to obtain ethyl3-bromo-4-mercaptobenzoate (2.58 g) as a light-yellow solid.

¹H-NMR (400M, CDCl₃) δ 1.39 (t, J=7.2 Hz, 3H), 4.20 (s, 1H), 4.36 (q,J=7.1 Hz, 2H), 7.38 (d, J=8.2 Hz, 1H), 7.82 (dd, J=8.2, 1.8 Hz, 1H),8.18 (d, J=1.8 Hz, 1H).

Reference Example 7{(2S)-6-(Ethoxycarbonyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid

The 4-nitrobenzyl (2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoate (5.43 g)described in Reference Example 5 was dissolved in acetonitrile (20 ml),followed by adding thereto trifluoroacetic anhydride (5.1 ml) and thentriethylamine (4.2 ml) at −30 to −20° C., and the resulting mixture wasallowed to warm to room temperature spontaneously. After 30 minutes, thereaction mixture was poured into a saturated aqueous ammonium chloridesolution and extracted with ethyl acetate, and the organic layer waswashed with a saturated aqueous sodium hydrogencarbonate solution and asaturated aqueous sodium chloride solution and dried over anhydroussodium sulfate. After the drying agent was removed by filtration, thesolvent was distilled off under reduced pressure and the residue wasdissolved in acetonitrile (20 ml). The compound described in ReferenceExample 6 (ethyl 3-bromo-4-mercaptobenzoate (4.14 g, 15.7 mmol)) andthen pyridine (1.28 ml, 15.7 mmol) were added thereto under ice-cooling.After 15 minutes, the resulting mixture was warmed up to roomtemperature. After 1 hour, the reaction mixture was poured into asaturated aqueous ammonium chloride solution and extracted with ethylacetate. The organic layer was washed with a saturated aqueous sodiumchloride solution and then dried over anhydrous sodium sulfate. Thedrying agent was removed by filtration and the solvent was distilled offunder reduced pressure. The residue was purified by a silica gel columnchromatography (hexane/ethyl acetate=4/1) to obtain ethyl3-bromo-4-[((1S)-4-(4-methoxyphenyl)-1-{[(4-nitrobenzyl)oxy]carbonyl}-butyl)thio]benzoate(6.89 g) having an optical purity of 99% e.e. The optical purityanalysis conditions are as follows. [Optical purity analysis conditions:column=OJ-R (Chiralcel, DAICEL Chemical Industries Ltd.); detectingwavelength (UV)=254 nm; flow rate: 1.0 ml/min; mobilephase=acetonitrile/water (68/32)]

¹H-NMR (CDCl₃) δ 1.39 (t, J=7.1 Hz, 3H), 1.65-1.87 (m, 2H), 1.93 (m,1H), 2.05 (m, 1H), 2.61 (m, 1H), 3.79 (s, 3H), 3.95 (t, J=6.9 Hz, 1H),4.37 (q, J=7.1 Hz, 2H), 5.17 (d, J=2.2 Hz, 2H), 6.79-6.83 (m, 2H),7.04-7.09 (m, 2H), 7.30-7.38 (m, 3H), 7.78 (dd, J=8.3, 1.8 Hz, 1H),8.10-8.18 (m, 3H).

Reference Example 8(2S)-2-{[2-Bromo-4-(ethoxycarbonyl)phenyl]thio}-5-(4-methoxyphenyl)pentanoicacid

Zinc (3.73 g) and ammonium chloride (3.69 g) were added to water (34.5ml), and a solution of the compound of Reference Example 7 (6.89 g, 99%e.e.) in THF (30 ml) was added dropwise thereto under ice-cooling. Aftercompletion of the dropwise addition, the resulting mixture was warmed upto room temperature and stirred for 6 hours. Ethyl acetate and waterwere added to the reaction mixture and the resulting mixture wasfiltered through Celite. The organic layer was washed with a 1N aqueoushydrochloric acid solution and a saturated aqueous sodium chloridesolution and dried over anhydrous sodium sulfate. The drying agent wasremoved by filtration and the solvent was distilled off under reducedpressure. The thus obtained(2S)-2-{[2-bromo-4-(ethoxycarbonyl)phenyl]thio}-5-(4-methoxyphenyl)pentanoicacid (96% e.e.) was used in a subsequent step. The optical purityanalysis conditions are as follows. [Optical purity analysis conditions:column=AD-H (Chiralcel, DAICEL Chemical Industries Ltd.); detectingwavelength (UV)=254 nm; flow rate: 1.0 ml/min; mobilephase=n-hexane/isopropyl alcohol/TFA (90/10/0.1)]

¹H-NMR (CDCl₃) δ: 1.38 (t, J=7.1 Hz, 3H), 1.75-1.96 (m, 3H), 2.03 (m,1H), 2.62 (t, J=7.3 Hz, 2H), 3.78 (s, 3H), 3.85 (t, J=7.1 Hz, 1H), 4.37(q, J=7.1 Hz, 2H), 6.79-6.83 (m, 2H), 7.08-7.10 (m, 2H), 7.41 (d, J=8.3Hz, 1H), 7.90 (dd, J=8.3, 1.8 Hz, 1H), 8.18 (d, J=1.8 Hz, 1H).

Reference Example 9 Ethyl3-bromo-4-({(1S)-4-(4-methoxyphenyl)-1-[(t-butoxycarbonylmethylamino)carbonyl]butyl}thio)benzoate

Glycine tert-butyl ester hydrochloride (2.03 g) anddicyclohexylcarbodiimide (DCC) (2.5 g) were added to a solution of(2S)-2-{[2-bromo-4-(ethoxycarbonyl)phenyl]thio}-5-(4-methoxyphenyl)pentanoicacid (the compound of Reference Example 8) (96% e.e.) in dichloromethane(56.4 ml) at −5° C., and N-methylmorpholine (1.26 ml) was added dropwisethereto. After stirring at the same temperature for 1.5 hours, water wasadded thereto and the resulting mixture was filtered through Celite. Thefiltrate was extracted with chloroform and the extract solution waswashed with a saturated aqueous ammonium chloride solution and asaturated aqueous sodium chloride solution and then dried over anhydroussodium sulfate. The drying agent was removed by filtration and thesolvent was distilled off under reduced pressure. The residue waspurified by a silica gel column chromatography (hexane/ethylacetate=3/1) to obtain ethyl3-bromo-4-({(1S)-4-(4-methoxyphenyl)-1-[(tert-butoxycarbonylmethylamino)carbonyl]butyl}thio)benzoate(4.83 g, 98% e.e.). The optical purity analysis conditions are asfollows. [Optical purity analysis conditions: column=AD-H (Chiralcel,DAICEL Chemical Industries Ltd.); detecting wavelength (UV)=254 nm; flowrate: 1.0 ml/min; mobile phase=n-hexane/isopropyl alcohol/TFA(90/10/0.1)]

¹H-NMR (CDCl₃) δ: 1.38 (t, J=7.1 Hz, 3H), 1.42 (s, 9H), 1.79-1.98 (m,3H), 2.09 (m, 1H), 2.62 (t, J=7.3 Hz, 2H), 3.77 (dd, J=18.2, 4.9 Hz,1H), 3.78 (s, 3H), 3.85 (t, J=6.9 Hz, 1H), 3.94 (dd, J=18.2, 5.6 Hz,1H), 4.36 (q, J=7.1 Hz, 2H), 6.79-6.83 (m, 2H), 6.95 (m, 1H), 7.08-7.12(m, 2H), 7.22 (d, J=8.4 Hz, 1H), 7.88 (dd, J=8.3, 1.8 Hz, 1H), 8.18 (d,J=1.8 Hz, 1H).

Reference Example 10 Ethyl(2S)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

The compound of Reference Example 9 (4.83 g, 98% e.e.) was dissolved intoluene (161 ml), and 1,1′-bis(diphenylphosphino)ferrocene (DPPF, 889mg) and cesium carbonate (2.61 g) were added thereto. After theresulting mixture was treated with nitrogen to replace the air,tris(dibenzylideneacetone)palladium(0) (Pd₂(dba)₃, 366 mg) was addedthereto, and the resulting mixture was stirred at 120° C. After 5 hours,the reaction mixture was cooled to room temperature and filtered throughCelite. The filtrate was poured into a saturated aqueous ammoniumchloride solution and extracted with ethyl acetate. The organic layerwas washed with a saturated aqueous sodium chloride solution and thendried over anhydrous magnesium sulfate. The drying agent was removed byfiltration and the residue was purified by a silica gel columnchromatography (hexane/ethyl acetate=5/1) to obtain ethyl(2S)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(2.37 g, 95% e.e.). The optical purity analysis conditions are asfollows. [Optical purity analysis conditions: column=OD-RH (Chiralcel,DAICEL Chemical Industries Ltd.); detecting wavelength (UV)=254 nm; flowrate: 1.0 ml/min; mobile phase=acetonitrile/water (60/40)]

¹H-NMR (CDCl₃) δ: 1.38 (t, J=7.1 Hz, 3H), 1.49 (s, 9H), 1.60 (m, 1H),1.71 (m, 1H), 1.75-1.98 (m, 2H), 2.54 (m, 2H), 3.48 (m, 1H), 3.76 (s,3H), 4.32-4.41 (m, 3H), 4.82 (m, 1H), 6.76-6.80 (m, 2H), 7.02-7.06 (m,2H), 7.40 (m, 1H), 7.50 (m, 1H), 7.70 (m, 1H).

Reference Example 11

{(2S)-6-(Ethoxycarbonyl)-2-[3-(4-methoxy-phenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid

Water (6.25 ml) was added to a solution of the compound of ReferenceExample 10 (2.57 g, 95% e.e.) in TFA (25 ml) under ice-cooling. After 5minutes, the resulting mixture was warmed up to room temperature andstirred for 1.5 hours. Toluene (60 ml) was added to the reactionsolution and distilled off under reduced pressure. Toluene and waterwere added to the residue to effect separation into two layers, and theorganic layer was washed with a saturated aqueous sodium chloridesolution and then dried over anhydrous sodium sulfate. The drying agentwas removed by filtration and the solvent was distilled off underreduced pressure to obtain{(2S)-6-(ethoxycarbonyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-2,3-dihydro-4H-1,4-benzothiazin-4-yl}aceticacid (2.06 g).

¹H-NMR (CDCl₃) δ: 1.39 (t, J=7.2 Hz, 3H), 1.60 (m, 1H), 1.70 (m, 1H),1.75-1.93 (m, 2H), 2.52 (m, 2H), 3.50 (m, 1H), 3.77 (s, 3H), 4.38 (q,J=7.2 Hz, 2H), 4.59 (m, 1H), 4.92 (m, 1H), 6.76-6.80 (m, 2H), 7.00-7.04(m, 2H), 7.41 (d, J=8.1 Hz, 1H), 7.55 (m, 1H), 7.71 (m, 1H).

Reference Example 12 (+)-Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Using 4-nitrobenzyl (2S)-2-hydroxy-5-(4-methoxyphenyl)pentanoate,(+)-ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatehaving an optical purity of 99.9% e.e. was synthesized by the sameprocess as described in Example 7. The optical purity was determined bythe method described in Example 7.

[α]_(D) ²⁰=+86.1° (c: 1.0, CHCl₃)

¹H-NMR (CDCl₃) δ: 1.40 (t, J=7.2 Hz, 3H), 1.59 (m, 1H), 1.67 (m, 1H),1.77-1.93 (m, 2H), 2.54 (m, 2H), 3.47 (m, 1H), 3.77 (s, 3H), 4.38 (q,J=7.2 Hz, 2H), 4.51 (d, J=16.0 Hz, 1H), 4.68 (d, J=16.0 Hz, 1H), 6.80(m, 2H), 7.04 (m, 2H), 7.41 (d, J=8.0 Hz, 1H), 7.52 (br, 1H), 7.73 (m,1H), 7.98 (br, 1H), 9.16 (br, 1H).

Reference Example 13(+)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

Using the compound of Reference Example 12,(+)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxy-phenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (99% e.e.) was obtained by a process similar to the processdescribed in Example 14. The optical purity was determined by the methoddescribed in Example 14.

¹H-NMR (DMSO-d6) δ 1.43 (m, 1H), 1.66 (m, 3H), 2.45 (m, 2H), 3.69 (s,3H), 4.38 (d, J=16.8 Hz, 1H), 4.54 (d, J=16.8 Hz, 1H), 6.80 (m, 2H),7.05 (m, 2H), 7.51 (m, 1H), 7.58-7.60 (m, 2H), 9.02+9.43 (s, 1H),10.36+10.81 (s, 1H), 13.20 (brs, 1H).

Reference Example 14 Ethyl(2R)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

The compound obtained in step B in Example 1 (62 mg) was dissolved inmethylene chloride (2.5 ml), followed by adding(−)-(8,8-dichlorocamphorylsulfonyl) oxaziridine (37 mg), and theresulting mixture was stirred at room temperature for 10 days. Thereaction mixture was poured into a saturated aqueous sodium chloridesolution and extracted with ethyl acetate. The organic layer wascollected, dried over anhydrous magnesium sulfate and then concentratedwith an evaporator. The residue was purified by a silica gel flashchromatography (hexane/ethyl acetate=4/1) to obtain ethyl(2R)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(15 mg, 85% e.e.) as a light-yellow oil. The optical purity wasdetermined by the method described in Reference Example 10.

Reference Example 15 (+)-Ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Using the compound of Example 1, the compound of Reference Example 12(17% and 81% e.e.) was obtained by the same process as described inReference Example 14. The optical purity was determined by the methoddescribed in Example 7.

Reference Example 16(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid

The compound of Example 14 (25% and 90% e.e.) was obtained by the sameprocess as described in Reference Example 14, except for using thecompound of Example 8, (+)-(8,8-dichlorocamphorylsulfonyl)oxaziridineand ethyl acetate as solvent. The optical purity was determined by themethod described in Example 14.

Reference Example 17 Ethyl (2E,4E)-5-(4-methoxyphenyl)penta-2,4-dienoate

After NaH (2.7 g, 60%) was washed with hexane, tetrahydrofuran (100 ml)was added thereto. The reaction mixture was cooled to 0° C. and thentriethyl phosphonoacetate (14.7 ml) was added dropwise thereto. After 30minutes, the resulting mixture was warmed up to room temperature andstirred for another 30 minutes. The reaction mixture was cooled to 0° C.again and a solution of the compound obtained in Reference Example 1 (10g) in tetrahydrofuran (50 ml) was added dropwise thereto. After 30minutes, a saturated aqueous ammonium chloride solution was addedthereto, followed by extraction with ethyl acetate. The organic layerwas washed with water, dried, and then concentrated, and the residue wascrystallized from ethanol-hexane. The crystals were filtered and thendried to obtain ethyl (2E,4E)-5-(4-methoxyphenyl)penta-2,4-dienoate(11.5 g).

¹H-NMR (CDCl₃) δ 1.31 (t, J=7.1 Hz, 3H), 3.83 (s, 3H), 4.22 (q, J=7.1Hz, 2H), 5.94 (d, J=15.2 Hz, 1H), 6.75 (dd, J=15.2, 10.7 Hz, 1H),6.82-6.93 (m, 3H), 7.38-7.48 (m, 3H).

Reference Example 18 5-(4-Methoxyphenyl)pentanoic acid

The compound obtained in Reference Example 17 (11.5 g), tetrahydrofuran(150 ml) and 10% Pd—C (1.5 g) were mixed and then stirred under ahydrogen atmosphere. After 3 hours, the reaction mixture was filteredthrough Celite and the filtrate was concentrated. Ethanol (150 ml) and a1N aqueous potassium hydroxide solution (50 ml) were added to theresidue and the resulting mixture was stirred with heating at 70° C. for30 minutes. Water was added thereto and the ethanol was concentrated.The thus obtained solution was acidified with a 1N aqueous hydrochloricacid solution and the precipitate formed was filtered and then dried toobtain 5-(4-methoxyphenyl)pentanoic acid (10.2 g).

¹H-NMR (CDCl₃) δ 1.59-1.73 (m, 4H), 2.35-2.41 (m, 2H), 2.55-2.63 (m,2H), 3.79 (s, 3H), 6.83 (m, 2H), 7.09 (m, 2H).

Reference Example 19(4R)-4-Benzyl-3-[5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one

5-(4-Methoxyphenyl)pentanoic acid (the compound obtained in ReferenceExample 18) (6.2 g) was dissolved in dichloromethane (60 ml), and oxalylchloride (3.1 ml) and DMF (a drop) were added thereto at roomtemperature. After 1 hour, the reaction mixture was concentrated, driedunder reduced pressure and then dissolved in tetrahydrofuran (20 ml) toobtain a solution named A.

(R)-4-Benzyl-2-oxazolidinone (6.4 g) was dissolved in tetrahydrofuran(80 ml) and the resulting solution was cooled to −78° C., followed byadding dropwise thereto n-butyllithium (1.58M, 23 ml). The resultingmixture was stirred for 1 hour and then the solution A prepared as abovewas added dropwise thereto. After 30 minutes, the resulting mixture waswarmed up to 0° C. and stirred for another 30 minutes. After thereaction was quenched with a saturated aqueous ammonium chloridesolution, the reaction mixture was extracted with ethyl acetate. Theorganic layer was washed with water, dried and then concentrated, andthe residue was purified by a silica gel chromatography (300 g, ethylacetate:hexane=1:3) to obtain(4R)-4-benzyl-3-[5-(4-methoxy-phenyl)pentanoyl]-1,3-oxazolidin-2-one(9.0 g).

¹H-NMR (CDCl₃) δ 1.63-1.79 (m, 4H), 2.57-2.65 (m, 2H), 2.75 (dd, J=13.3,9.6 Hz, 1H), 2.88-3.04 (m, 2H), 3.29 (dd, J=13.3, 3.3 Hz, 1H), 3.79 (s,3H), 4.13-4.22 (m, 2H), 4.66 (m, 1H), 6.83 (m, 2H), 7.11 (m, 2H), 7.20(m, 2H), 7.25-7.36 (m, 3H).

Reference Example 20(4R)-3-[5-(4-Methoxyphenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one

(4R)-3-[5-(4-Methoxyphenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one (2.6g) was obtained from 5-(4-methoxyphenyl)pentanoic acid (2 g) and(R)-4-phenyl-2-oxazolidinone (1.6 g) by a process similar to the processdescribed in Reference Example 19.

¹H-NMR (CDCl₃) δ 1.55-1.70 (m, 4H), 2.54 (t, J=6.8 Hz, 2H), 2.95 (t,J=7.5 Hz, 2H), 3.78 (s, 3H), 4.27 (dd, J=8.9, 3.7 Hz, 1H), 4.68 (t,J=8.9 Hz, 1H), 5.41 (dd, 1H, J=8.9, 3.7 Hz, 1H), 6.80 (m, 2H), 7.05 (m,2H), 7.26 (m, 5H).

Reference Example 21(4R)-4-Benzyl-3-[(2R)-2-bromo-5-(4-methoxy-phenyl)pentanoyl]-1,3-oxazolidin-2-one

(4R)-4-Benzyl-3-[5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one(Reference Example 19) (1.4 g) was dissolved in dichloromethane (25 ml),and dibutylborane triflate (1M, 8.3 ml) and diisopropylethylamine (1.6ml) were added thereto under ice-cooling. After 30 minutes, the reactionmixture was cooled to −78° C. and added dropwise to a solution ofN-bromosuccinimide (NBS) (1.1 g) in dichloromethane (25 ml) which hadbeen cooled to −78° C., via a cannula. After 2 hours, an aqueous sodiumsulfite solution was added thereto and the resulting mixture was stirredat room temperature for 30 minutes. Chloroform was added to the reactionmixture to effect separation and extraction. The organic layer wasdried, concentrated, and then the residue was purified by a silica gelchromatography (150 g, ethyl acetate:hexane=1:4) to obtain(4R)-4-benzyl-3-[(2R)-2-bromo-5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one(0.9 g).

¹H-NMR (CDCl₃) δ 1.62-1.89 (m, 2H), 2.04-2.22 (m, 2H), 2.56-2.70 (m,2H), 2.79 (dd, J=13.5, 9.5 Hz, 1H), 3.29 (dd, J=13.5, 3.3 Hz, 1H), 3.78(s, 3H), 4.20-4.23 (m, 2H), 4.68 (m, 1H), 5.63 (t, J=6.8 Hz, 1H), 6.83(m, 2H), 7.10 (m, 2H), 7.22-7.38 (m, 5H).

Reference Example 22 Ethyl4-{[(1S)-1-{[(4R)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate

Diethyl 4,4′-dithiobis(3-nitrobenzoate) (0.64 g) was dissolved intetrahydrofuran (10 ml), and dithiothreitol (0.24 g) andN-methylmorpholine (0.21 ml) were added thereto at room temperature.After 40 minutes, the reaction mixture was cooled to 0° C. and asolution of(4R)-4-benzyl-3-[(2R)-2-bromo-5-(4-methoxyphenyl)pentanoyl]-1,3-oxazolidin-2-one(Reference Example 21) (0.7 g) in tetrahydrofuran (10 ml) was slowlyadded dropwise thereto. After 2 hours, the reaction was quenched by theaddition of a 1N aqueous hydrochloric acid solution (20 ml) and thereaction mixture was extracted with ethyl acetate. The organic layer waswashed with a saturated aqueous sodium hydrogencarbonate solution, waterand a saturated aqueous sodium chloride solution, dried, concentrated,and then the residue was purified by a silica gel chromatography (150 g,ethyl acetate:hexane=1:4) to obtain ethyl4-{[(1S)-1-{[(4R)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate(0.7 g).

¹H-NMR (CDCl₃) δ 1.42 (t, J=7.1 Hz, 3H), 1.78-2.00 (m, 3H), 2.19 (m,1H), 2.64 (m, 1H), 2.74 (dd, J=13.3, 9.7 Hz, 1H), 3.30 (dd, J=13.3, 3.3Hz, 1H), 3.79 (s, 3H), 4.19-4.30 (m, 2H), 4.42 (q, J=7.1 Hz, 2H), 4.70(m, 1H), 5.53 (t, J=7.3 Hz, 1H), 6.82 (m, 2H), 7.10 (m, 2H), 7.19 (m,2H), 7.25-7.35 (m, 3H), 7.48 (d, J=8.5 Hz, 1H), 8.11 (dd, J=8.5, 1.9 Hz,1H), 8.73 (d, J=1.9 Hz, 1H).

Reference Example 23 Ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Ethyl4-{[(1S)-1-{[(4R)-4-benzyl-2-oxo-1,3-oxazolidin-3-yl]carbonyl}-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate(Reference Example 22) (0.62 g, 0.11 mmol), ethanol (10 ml), acetic acid(5 ml) and 10% Pd—C (1.5 g) were mixed, and the mixture was stirred for3 hours at room temperature under a hydrogen atmosphere. The reactionmixture was filtered through Celite and the filtrate was concentrated.The residue was purified by a silica gel chromatography (40 g, ethylacetate:hexane=1:3) to obtain ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(0.2 g, 98.3% e.e.), i.e., the compound described in Example 7.

The optical purity analysis conditions are as follows:

Column: AD-H (Chiralcel, DAICEL Chemical Industries Ltd.)

Detecting wavelength (UV): 254 nm

Flow rate: 1.0 ml/min

Mobile phase=n-hexane/isopropyl alcohol/TFA=80/20/0.1

¹H-NMR (CDCl₃) δ 1.40 (t, J=7.1 Hz, 3H), 1.60-1.75 (m, 2H), 1.80-1.98(m, 2H), 2.56 (m, 2H), 3.44 (m, 1H),3.77 (s, 3H), 4.38 (q, J=7.1 Hz,2H), 6.78-6.82 (m, 2H), 7.03-7.08 (m, 2H), 7.35 (d, J=8.1 Hz, 1H), 7.55(d, J=1.5 Hz, 1H), 7.67 (dd, J=8.1, 1.5 Hz, 1H), 8.52 (s, 1H).

Reference Example 24(4R)-3-[(2R)-2-Hydroxy-5-(4-methoxy-phenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one

(4R)-3-[5-(4-Methoxyphenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one(Reference Example 20) (1.0 g) was dissolved in tetrahydrofuran (10 ml)and the resulting solution was cooled to −78° C., followed by addingthereto sodium hexamethyldisilazide (1M, 3.4 ml). After 30 minutes, asolution of Davis reagent (0.9 g) in tetrahydrofuran (5 ml) was addeddropwise thereto. After stirring for 1 hour, a solution ofcamphorsulfonic acid (1.5 g) in tetrahydrofuran (5 ml) was added theretoand stirred for 30 minutes. Ethyl acetate and water were added to thereaction mixture to effect separation and extraction. The organic layerwas washed with a saturated aqueous sodium hydrogencarbonate solution,water and a saturated aqueous sodium chloride solution, dried,concentrated, and then the residue was purified by a silica gelchromatography (100 g, ethyl acetate:hexane=1:3) to obtain(4R)-3-[(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one(0.75 g).

¹H-NMR (CDCl₃) δ 1.59 (m, 1H), 1.75-1.92 (m, 3H), 2.60 (m, 2H), 3.78 (s,3H), 4.35 (dd, J=8.7, 3.2 Hz, 1H), 4.75 (t, J=8.7 Hz, 1H), 5.01 (dd,J=8.1, 3.2 Hz, 1H), 5.38 (dd, J=8.7, 3.2 Hz, 1H), 6.82 (m, 2H), 7.10 (m,2H), 7.26-7.42 (m, 5H).

Reference Example 25 Methyl(2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoate

(4R)-3-[(2R)-2-Hydroxy-5-(4-methoxy-phenyl)pentanoyl]-4-phenyl-1,3-oxazolidin-2-one(Reference Example 24) (0.23 g) was dissolved in methanol (3 ml), andsodium methoxide (a 1.2M methanol solution, 1 ml) was added theretounder ice-cooling. After 5 minutes, the reaction was quenched by addinga saturated aqueous ammonium chloride solution to the reaction mixture,and then the reaction mixture was extracted with ethyl acetate. Theorganic layer was washed with water, dried, concentrated, and then theresidue was purified by a silica gel chromatography (20 g, ethylacetate:hexane=1:3) to obtain methyl(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoate (0.06 g, 98% e.e.).

The optical purity analysis conditions are as follows:

Column: OD-H (Chiralcel, DAICEL Chemical Industries Ltd.)

Detecting wavelength (UV): 276 nm

Flow rate: 1.0 ml/min

Mobile phase=n-hexane/isopropyl alcohol=90/10

¹H-NMR (CDCl₃) δ 1.60-1.87 (m, 4H), 2.55-2.62 (m, 2H), 2.73 (br., 1H),3.76 (s, 3H), 3.77 (s, 3H), 4.20 (m, 1H), 6.80-6.84 (m, 2H), 7.06-7.12(m, 2H).

Reference Example 26 (2R)-2-Hydroxy-5-(4-methoxyphenyl)pentanoic acid

5-(4-Methoxyphenyl)-2-oxopentanoic acid (62.7 g) was dissolved in THF (1L) and triethylamine (46.8 ml) was added thereto. A solution of(−)-DIP-Cl (100 g) in THF (600 ml) was added dropwise thereto whilemaintaining the temperature at −25° C. to −35° C. The resulting mixturewas warmed up to room temperature and stirred for 2 hours, and thenwater (500 ml) was added thereto at 20° C. or lower. A 6N aqueous sodiumhydroxide solution (120 ml) was added thereto and stirred for 15minutes. Thereafter, diisopropyl ether (300 ml) was added thereto toeffect separation into two layers. The aqueous layer was washed twicewith diisopropyl ether (300 ml) and then a 6N aqueous hydrochloric acidsolution was added thereto, followed by extraction with ethyl acetate.The organic layer was washed with a saturated aqueous sodium chloridesolution and then dried over anhydrous sodium sulfate. The solvent wasdistilled off under reduced pressure to obtain a crude product. Thecrude product was dissolved in acetonitrile (640 ml), followed by addingthereto (+)-tolylethylamine (39 g), and the resulting mixture was heatedunder reflux to dissolve the amine completely. Crystals wereprecipitated at room temperature and collected by filtration. A 1Naqueous hydrochloric acid solution was added to the crystals obtained,followed by extraction with ethyl acetate. The organic layer was washedwith a saturated aqueous sodium chloride solution and then dried overanhydrous sodium sulfate. The solvent was distilled off under reducedpressure and the residue was crystallized from a mixed solvent ofdiisopropyl ether and hexane (1/1) to obtain(2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoic acid (29.8 g, 98% e.e.).

The optical purity was determined by the method described in ReferenceExample 4.

¹H NMR (300 MHz, CDCl₃) δ 1.70-1.89 (m, 4H), 2.60 (brt, J=6.6 Hz, 2H),3.79 (s, 3H), 4.27-4.29 (m, 1H), 6.80-6.85 (m, 2H), 7.08-7.11 (m, 2H).

Reference Example 27 Methyl (2R)-2-hydroxy-5-(4-methoxyphenyl)pentanoate

The compound obtained in Reference Example 26 (134 g, 98% e.e.) wasdissolved in methanol (1072 ml), followed by adding thereto concentratedsulfuric acid (13.4 ml), and the resulting mixture was stirred at 60° C.for 1 hour. About one-half of the methanol was distilled off underreduced pressure and the residual reaction solution was poured intowater (1 L). After extraction with ethyl acetate (600 ml+300 ml), theorganic layer was washed with a saturated aqueous sodiumhydrogencarbonate solution and a saturated aqueous sodium chloridesolution and then dried over anhydrous sodium sulfate. The solvent wasdistilled off under reduced pressure to obtain methyl2-hydroxy-5-(4-methoxyphenyl)pentanoate quantitatively (98% e.e.). Theoptical purity analysis conditions are as follows. [Optical purityanalysis conditions: column=OD-H (Chiralcel, DAICEL Chemical IndustriesLtd.); detecting wavelength (UV)=276 nm; flow rate: 1.0 ml/min; mobilephase=n-hexane/isopropyl alcohol (90/10)]

¹H-NMR (CDCl₃) δ 1.60-1.87 (m, 4H), 2.55-2.62 (m, 2H), 2.73 (br., 1H),3.76 (s, 3H), 3.77 (s, 3H), 4.20 (m, 1H), 6.80-6.84 (m, 2H), 7.06-7.12(m, 2H).

Reference Example 28 (2S)-2-Hydroxy-5-(4-methoxyphenyl)pentanoic acid

(2S)-2-Hydroxy-5-(4-methoxyphenyl)pentanoic acid was obtained by thesame process as described in Reference Example 26, except for using(+)-DIP-Cl in place of (−)-DIP-Cl, and (−)-tolylethylamine in place of(+)-tolylethylamine. (The optical purity was 97% e.e.).

The optical purity was determined by the method described in ReferenceExample 4.

¹H-NMR (CDCl₃) δ 1.66-1.92 (m, 4H), 2.61 (m, 1H), 3.78 (s, 3H), 4.26 (m,1H), 6.80-6.85 (m, 2H), 7.03-7.12 (m, 2H).

Reference Example 29 Diethyl 4,4′-dithiobis(3-nitrobenzoate)

Step O

To potassium carbonate (103 g) was added DMF (1 L), and a solution of3-nitro-4-chlorobenzoic acid (125 g) in DMF (500 ml) was added theretounder ice-cooling. Ethyl iodide (116 g) was added thereto and theresulting mixture was stirred at 60° C. for 3 hours. The reactionsolution was added to a 1N aqueous hydrochloric acid solution and thecrystals precipitated were collected by filtration, washed with a 1Naqueous hydrochloric acid solution and water and then dried underreduced pressure to obtain ethyl 4-chloro-3-nitrobenzoatequantitatively.

¹H-NMR (CDCl₃) δ 1.42 (t, J=7.1 Hz, 3H), 4.43 (q, J=7.1 Hz, 2H), 7.65(d, J=8.4 Hz, 1H), 8.17 (dd, J=8.4, 2.0 Hz, 1H), 8.52 (d, J=2.0 Hz, 1H).

Step P

Ethyl 4-chloro-3-nitrobenzoate (113 g) was dissolved in ethanol (1 L)and potassium thioacetate (58.9 g) was added thereto at roomtemperature. The resulting mixture was stirred at 60° C. for 30 minutesand cooled to room temperature, and the crystals precipitated werecollected by filtration. After the crystals were washed with ethanol andthen water, acetonitrile (200 ml) was added thereto, and the resultingmixture was heated under reflux for 15 minutes. After cooling to roomtemperature, the crystals were collected by filtration and dried toobtain diethyl 4,4′-dithiobis(3-nitrobenzoate) (57.1 g).

¹H-NMR (400M, DMSO-d6) δ 1.32 (t, J=6.8 Hz, 6H), 4.35 (q, J=7.2 Hz, 4H),8.01 (m, 2H), 8.15 (m, 2H), 8.94 (s, 2H).

Reference Example 30 Ethyl4-{[(1S)-1-(methoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate

The methyl (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoate (10 g, 98%e.e.) synthesized in Reference Example 27 was dissolved in acetonitrile(50 mL), followed by adding trifluoromethanesulfonic acid anhydride (9ml) and then triethylamine (6.5 ml) under ice-cooling, and the resultingmixture was stirred at the same temperature for 1 hour. A saturatedaqueous ammonium chloride solution was added thereto, followed byextraction with ethyl acetate. The organic layer was washed with asaturated aqueous sodium hydrogencarbonate solution and a saturatedaqueous sodium chloride solution and then dried over anhydrous sodiumsulfate. The solvent was distilled off under reduced pressure and theresidue was dissolved in THF (50 ml) (a solution A).

The compound of Reference Example 29 (diethyl4,4′-dithiobis(3-nitrobenzoate)) (12.1 g) was added to THF (60 ml), anddithiothreitol (4.8 g) and then N-methylmorpholine (5.9 ml) were addedthereto under a nitrogen atmosphere. The resulting mixture was stirredfor 30 minutes to prepare a solution of ethyl 4-thio-3-nitrobenzoate.Although this ethyl 4-thio-3-nitrobenzoate was isolatable, the solutionwas used as it was in the subsequent reaction. The solution was addeddropwise to the above-mentioned THF solution A under ice-cooling and theresulting mixture was stirred at the same temperature for 30 minutes. A1N aqueous hydrochloric acid solution (110 ml) was added thereto underice-cooling, followed by extraction with ethyl acetate (100 ml). Theorganic layer was washed with a saturated aqueous sodiumhydrogen-carbonate solution and a saturated aqueous sodium chloridesolution and then dried over anhydrous sodium sulfate. The solvent wasdistilled off under reduced pressure to obtain ethyl4-{[(1S)-1-(methoxycarbonyl)-4-(4-methoxy-phenyl)butyl]thio}-3-nitrobenzoate(96% e.e.). This compound was used in a subsequent step withoutpurification. The optical purity analysis conditions are as follows:

Column: AD-H (Chiralcel, DAICEL Chemical Industries Ltd.)

Detecting wavelength (UV): 254 nm

Flow rate: 1.0 ml/min

Mobile phase=n-hexane/isopropyl alcohol/TFA=95/5/0.1

¹H-NMR (CDCl₃) δ: 1.41 (t, J=7.1 Hz, 3H), 1.70-1.98 (m, 3H), 2.05 (m,1H), 2.62 (m, 2H), 3.72 (s, 3H), 3.78 (s, 3H), 3.94 (t, J=7.0 Hz, 1H),4.41 (q, J=7.1 Hz, 2H), 6.78-6.84 (m, 2H), 7.06-7.09 (m, 2H), 7.62 (d,J=8.6 Hz, 1H), 8.14 (dd, J=8.5, 1.9 Hz, 1H), 8.82 (d, J=1.9 Hz, 1H).

Reference Example 31 Ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Acetic acid (50 ml) was added to reduced iron (8.2 g) and a solution ofthe compound obtained in Reference Example 30 in toluene (50 ml, theinsoluble material was removed by Kiriyama filtration) was added theretoat 90° C. The resulting mixture was stirred at the same temperature for5 hours, cooled to room temperature and then filtered through Celite.The filtrate was poured into a 1N aqueous hydrochloric acid solution(200 ml). After extraction with ethyl acetate (100 ml), the organiclayer was washed with a saturated aqueous sodium chloride solution anddried over anhydrous sodium sulfate. The solvent was distilled off underreduced pressure and the residue was recrystallized from a mixed solventof diisopropyl ether (250 ml) and ethyl acetate (50 ml) to obtain ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(8.71 g, 98% e.e.). The optical purity was determined by the methoddescribed in Reference Example 23.

¹H-NMR (CDCl₃) δ 1.40 (t, J=7.1 Hz, 3H), 1.60-1.75 (m, 2H), 1.80-1.98(m, 2H), 2.56 (m, 2H), 3.44 (m, 1H), 3.77 (s, 3H), 4.38 (q, J=7.1 Hz,2H), 6.78-6.82 (m, 2H), 7.03-7.08 (m, 2H), 7.35 (d, J=8.1 Hz, 1H), 7.55(d, J=1.5 Hz, 1H), 7.67 (dd, J=8.1, 1.5 Hz, 1H), 8.52 (s, 1H).

Reference Example 32 Ethyl(2S)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

The above-mentioned product (21.7 g, 98% e.e.) was dissolved in DMF (450ml) and cesium carbonate (18.33 g) was added thereto at 4° C. tert-Butylbromoacetate (21.95 g) was added thereto and stirred overnight. Cesiumcarbonate (9.17 g) was added thereto and the resulting mixture wasstirred at room temperature for 2 hours. Then, the reaction solution waspoured into a saturated aqueous ammonium chloride solution underice-cooling. After extraction with a mixed solvent of ethyl acetate (500ml) and toluene (200 ml), the organic layer was washed with a saturatedaqueous ammonium chloride solution and a saturated aqueous sodiumchloride solution and then dried over anhydrous sodium sulfate. Thesolvent was distilled off under reduced pressure to obtain ethyl(2S)-4-(2-tert-butoxy-2-oxoethyl)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate(97% e.e.) as a crude product. This crude product was used in asubsequent step without purification. The optical purity was determinedby the method described in Reference Example 10.

¹H-NMR (CDCl₃) δ 1.38 (t, J=7.1 Hz, 3H), 1.49 (s, 9H), 1.60 (m, 1H),1.71 (m, 1H), 1.75-1.98 (m, 2H), 2.54 (m, 2H), 3.48 (m, 1H), 3.76 (s,3H), 4.32-4.41 (m, 3H), 4.82 (m, 1H), 6.76-6.80 (m, 2H), 7.02-7.06 (m,2H), 7.40 (m, 1H), 7.50 (m, 1H), 7.70 (m,11H).

Reference Example 33 Ethyl (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoate

Using (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoic acid (80% e.e.),ethyl 2-hydroxy-5-(4-methoxyphenyl)pentanoate was quantitativelyobtained (80% e.e.) by a process similar to the process described inReference Example 27. The optical purity analysis conditions are asfollows: Column: AD-H (Chiralcel, DAICEL Chemical Industries Ltd.)

Detecting wavelength (UV): 276 nm

Flow rate: 1.0 ml/min

Mobile phase=n-hexane/isopropyl alcohol=90/10

¹H-NMR (CDCl₃) δ 1.28 (t, J=7.1 Hz, 3H), 1.60-1.90 (m, 4H), 2.50-2.70(m, 2H), 2.76 (m, 1H), 3.78 (s, 3H), 4.15-4.23 (m, 1H), 4.23 (q, J=7.1Hz, 2H), 6.78-6.84 (m, 2H), 7.06-7.12 (m, 2H).

Reference Example 34 Ethyl4-{[(1S)-1-(ethoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate

Using the ethyl (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoate (80% e.e.)described in Reference Example 33, ethyl4-{[(1S)-1-(ethoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate(80% e.e.) was obtained by a process similar to the process described inReference Example 30. The optical purity was determined by the methoddescribed in Reference Example 30.

¹H-NMR (CDCl₃) δ 1.22 (t, J=7.1 Hz, 3H), 1.42 (t, J=7.1 Hz, 3H),1.70-1.98 (m, 3H), 2.05 (m, 1H), 2.63 (m, 2H), 3.79 (s, 3H), 3.92 (t,J=7.0 Hz, 1H), 4.09-4.26 (m, 2H), 4.42 (q, J=7.1 Hz, 2H), 6.80-6.84 (m,2H), 7.06-7.10 (m, 2H), 7.64 (d, J=8.6 Hz, 1H), 8.14 (dd, J=8.5, 1.9 Hz,1H), 8.80 (d, J=1.9 Hz, 1H).

Reference Example 35 Ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate

Using ethyl4-{[(1S)-1-(ethoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate(80% e.e.), ethyl(2S)-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylatewas quantitatively obtained (91% e.e.) by a process similar to theprocess described in Reference Example 31. The optical purity wasdetermined by the method described in Reference Example 23.

¹H-NMR (CDCl₃) δ 1.40 (t, J=7.1 Hz, 3H), 1.60-1.75 (m, 2H), 1.80-1.98(m, 2H), 2.56 (m, 2H), 3.44 (m, 1H), 3.77 (s, 3H), 4.38 (q, J=7.1 Hz,2H), 6.78-6.82 (m, 2H), 7.03-7.08 (m, 2H), 7.35 (d, J=8.1 Hz, 1H), 7.55(d, J=1.5 Hz, 1H), 7.67 (dd, J=8.1, 1.5 Hz, 1H), 8.52 (s, 1H).

Reference Example 36 (2S)-2-Hydroxy-5-(4-methoxyphenyl)pentanoic acid

Using (S)-tolylethylamine, (2S)-2-hydroxy-5-(4-methoxyphenyl)pentanoicacid having an optical purity of 97% e.e. was obtained from the compoundof Reference Example 3 as starting material by a process similar to theprocess described in Reference Example 4. The optical purity wasdetermined by the method described in Reference Example 4.

¹H-NMR (CDCl₃) δ 1.66-1.92 (m, 4H), 2.61 (m, 1H), 3.78 (s, 3H), 4.26 (m,1H), 6.80-6.85 (m, 2H), 7.03-7.12 (m, 2H).

Reference Example 37 2-Bromo-5-(4-methoxyphenyl)pentanoic acid

At −5° C., sodium nitrite (176 mg) was slowly added to a solution ofpotassium bromide (591 mg) in a 0.75M aqueous hydrobromic acid solutionand then 2-amino-5-(4-methoxyphenyl)pentanoic acid (300 mg) was addedthereto. After stirring at the same temperature for 2 hours, thereaction mixture was poured into water (50 ml) and extracted with ethylacetate (20 ml×twice). The organic layer was collected, washed with asaturated aqueous sodium chloride solution (30 ml), dried over sodiumsulfate, and then concentrated under reduced pressure.2-Bromo-5-(4-methoxyphenyl)pentanoic acid was obtained as 355 mg of acrude product.

¹H-NMR (CDCl₃) δ 1.65-1.84 (m, 2H), 1.95-2.18 (m, 2H), 2.59-2.63 (m,2H), 3.79 (s, 3H), 4.24 (t, J=6.8 Hz, 1H), 6.82-6.85 (m, 2H), 7.08-7.11(m, 2H).

Reference Example 38 Ethyl 2-bromo-5-(4-methoxyphenyl)pentanoate

Concentrated sulfuric acid (1 ml) was added to a solution of the2-bromo-5-(4-methoxyphenyl)pentanoic acid crude product (ReferenceExample 37) (1000 mg) in ethanol (15 ml) at room temperature and theresulting mixture was heated under reflux for 2 hours. After beingallowed to cool to room temperature, the reaction solution was pouredinto water (50 ml) and extracted with ethyl acetate (50 ml). The organiclayer was washed with a saturated aqueous sodium hydrogencarbonatesolution (30 ml) and a saturated aqueous sodium chloride solution (30ml) and then dried over sodium sulfate. The dried organic layer wasconcentrated under reduced pressure and the crude product thus obtainedwas purified by HPLC to obtain ethyl2-bromo-5-(4-methoxyphenyl)pentanoate (740 mg).

¹H-NMR (CDCl₃) δ 1.59-1.81 (m, 2H), 1.95-2.15 (m, 2H), 2.58-2.62 (m,2H), 3.79 (s, 3H), 4.18-4.25 (m, 3H), 6.81-6.85 (m, 2H), 7.07-7.10 (m,2H).

Reference Example 39 Methyl 2-bromo-5-(4-methoxyphenyl)pentanoate

To a solution of methyl 5-(4-methoxy-phenyl)pentanoate (ReferenceExample 18) (100 mg) in tetrahydrofuran (5 ml) was added LHMDS (1.0M inTHF, 0.54 ml) at −78° C. under a nitrogen atmosphere. After stirring atthe same temperature for 1 hour, TMSCl (63 μl) was added thereto and theresulting mixture was stirred for 50 minutes and then stirred at roomtemperature for another 10 minutes. The reaction mixture wasconcentrated under reduced pressure and hexane (10 ml) was addedthereto. After the precipitate was filtered off, the filtrate wasconcentrated under reduced pressure again. To the resulting residue wasadded dimethylformamide (5 ml), followed by adding NBS (97 mg) at −78°C., and the resulting mixture was allowed to warm to room temperaturespontaneously. The reaction mixture was poured into water (20 ml) andextracted with ethyl acetate (20 ml). The organic layer was washed witha saturated aqueous sodium chloride solution (20 ml) and then dried oversodium sulfate. The dried organic layer was concentrated under reducedpressure and the crude product thus obtained was purified by a columnchromatography (hexane:ethyl acetate=5:1) to obtain methyl2-bromo-5-(4-methoxyphenyl)pentanoate (34.2 mg).

¹H-NMR (CDCl₃) δ 1.58-1.68 (m, 1H), 1.72-183 (m, 1H), 1.99-2.12 (m, 2H),2.54-2.63 (m, 2H), 3.77 (s, 3H), 3.78 (s, 3H), 4.22 (dd, 1H, J=7.8, 6.9Hz), 6.81-6.85 (m, 2H), 7.06-7.12 (m, 2H).

Reference Example 40 Diethyl 4,41-dithiobis(3-nitrobenzoate)

Under a nitrogen atmosphere, ethyl 4-chloro-3-nitrobenzoate (60.00 g)was suspended in ethanol (300 ml) and NaSH nH₂O (c.a. 70 wt %, 21.94 g)was added thereto under ice-cooling. After 30 minutes, the resultingmixture was stirred for 1 hour on a water bath at 20° C. to obtain ethyl4-thio-3-nitrobenzoate. An aqueous solution (water 780 ml) of NaHCO₃(60.00 g) and then iodine (33.16 g) were added to the ethyl4-thio-3-nitrobenzoate and stirred for 1 hour. The crystals in thereaction mixture in the form of a homogeneous yellow slurry werefiltered. After the crystals were washed with ethanol/water (1/1 (v/v),200 ml), acetonitrile (200 ml) was added to the crystals and theresulting mixture was heated under reflux for 15 minutes. After thismixture was cooled to room temperature and stirred for 2 hours, thecrystals were filtered and then washed with acetonitrile/water (1/1(v/v), 200 ml). Water (400 ml) was added to the crystals and stirred.Thereafter, the crystals were filtered, washed with water (200 ml) andthen dried to obtain diethyl 4,4′-dithiobis(3-nitrobenzoate) (50.95 g).

¹H-NMR (400M, DMSO-d6) δ 1.32 (t, J=6.8 Hz, 6H), 4.35 (q, J=7.2 Hz, 4H),8.01 (m, 2H), 8.15 (m, 2H), 8.94 (s, 2H).

Reference Example 41 Ethyl 4-thio-3-nitrobenzoate

Under a nitrogen atmosphere, ethyl 4-chloro-3-nitrobenzoate (1.00 g) wassuspended in ethanol (10 ml) and NaSH nH₂O (c.a. 70 wt %, 0.34 g) wasadded thereto under ice-cooling. After 30 minutes, the resulting mixturewas stirred for 1 hour on a water bath at 20° C. The ethanol wasconcentrated to one-half of its original volume and then water was addedto the residual reaction mixture, followed by extraction with toluene.The organic layer was concentrated under reduced pressure to obtainethyl 4-thio-3-nitrobenzoate (1.00 g).

¹H-NMR (400M, DMSO-d6) δ 1.34 (t, J=7.1 Hz, 3H), 4.35 (q, J=7.1 Hz, 2H),7.94 (m, 1H), 8.06 (m, 1H), 8.61 (s, 1H).

Reference Example 42 Ethyl 4-thio-3-nitrobenzoate

Under a nitrogen atmosphere, diethyl 4,4′-dithiobis(3-nitrobenzoate)(22.8 g) was suspended in ethanol (151 ml), and sodium tetrahydroborate(4.79 g) was added thereto in small portions under ice-cooling andstirred for 1 hour. A 1N aqueous hydrochloric acid solution (554 ml) wasadded to the reaction mixture under ice-cooling, followed by extractionwith toluene (228 ml×2). The organic layer was washed with water (114ml) and then distilled under reduced pressure to remove the solvent,whereby ethyl 4-thio-3-nitrobenzoate was quantitatively obtained asyellow needles.

Reference Example 43 Ethyl4-{[(1S)-1-(methoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate

The methyl (2R)-2-hydroxy-5-(4-methoxy-phenyl)pentanoate (20.0 g, 96%e.e.) synthesized in Reference Example 27 was dissolved in acetonitrile(100 ml), followed by adding thereto trifluoromethanesulfonic acidanhydride (17 ml) and then triethylamine (12.3 ml) under ice-cooling,and the resulting mixture was stirred at the same temperature for 1hour. Water (200 ml) was added thereto under ice-cooling, followed byextraction with toluene (200 ml×2). The organic layer was washed withwater (200 ml), a saturated aqueous sodium hydrogencarbonate solution(200 ml) and water (200 ml) and then distilled under reduced pressure toremove the solvent. The brown oil thus obtained was dissolved in THF (50ml) (a solution A).

A solution of the compound obtained in Reference Example 41 or ReferenceExample 42 (ethyl 4-thio-3-nitrobenzoate) (22.8 g) in THF (50 ml) wasadded dropwise to the above-mentioned THF solution A under ice cooling.A solution of N-methylmorpholine (11.1 ml) in THF (120 ml) was slowlyadded dropwise to the reaction mixture while paying attention to heatgeneration, and the resulting mixture was stirred at the sametemperature for 30 minutes. A 1N aqueous hydrochloric acid solution (220ml) was added thereto under ice-cooling, followed by extraction withtoluene (220 ml×2). The organic layer was washed with water (220 ml), asaturated aqueous sodium hydrogencarbonate solution (110 ml×2) and water(110 ml×2) and then distilled under reduced pressure to remove thesolvent, whereby ethyl4-{[(1S)-1-(methoxycarbonyl)-4-(4-methoxyphenyl)butyl]thio}-3-nitrobenzoate(95% e.e.) was obtained. This compound was used in a subsequent stepwithout purification. The optical purity was determined by the methoddescribed in Reference Example 30.

Formulation Example 1 Tablets

(−)-Ethyl 4-[2-(hydroxyamino)-2-oxoethyl]-2- 50 mg[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate Lactose 93 mg Corn starch 40mg Hydroxypropylmethyl cellulose 2910  6 mg Carmelose calcium 10 mgMagnesium stearate  1 mg

The above ingredients were mixed each in an amount of 100 times theamount specified above, and 200 mg of the resulting mixed powder wascompressed at a pressure of 50 kgf with a hydraulic press (mfd. by RikenCo. Ltd.) to obtain 100 tablets having a diameter of 8 mm and a weightof 200 mg.

Formulation Example 2 Capsules

(−)-Ethyl 4-[2-(hydroxyamino)-2-oxoethl]-2- 100 mg [3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate Lactose 100 mg  Corn starch39 mg Carmelose calcium 10 mg Magnesium stearate  1 mg

The above ingredients were mixed each in an amount of 100 times theamount specified above, and the resulting mixed powder was packed incapsules of No. 2 to obtain 100 capsules each having 250 mg of thecontents.

Formulation Example 3 Injection

(−)-4-[2-(Hydroxyamino)-2-oxoethyl]-2-[3-(4- 50 mgmethoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylic acid N-methylglucamine 23 mg Sodiumchloride 22.5 mg   Water for injection 2404 mg 

N-methylglucamine (23 mg) and sodium chloride (22.5 mg) were mixed with(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid (50 mg), and water for injection was added thereto to carry out anadjustment. The liquid thus obtained was filled into a vial to obtain anintra-articular injection.

Test Example 1 Oral Absorbability Evaluation Test

Each of the compounds of Example 7 and Example 14 was orallyadministered to each of Crj:CD (SD) strain male rats (Charles RiverJapan Inc.) aged 7 weeks in a dose of 30 mg/kg without fasting.

Blood was collected from each rat under etherisation 15 and 30 minutesand 1, 2, 4, 6 and 24 hours after the administration, and serum wasobtained from the blood and stored at −20° C. or lower till analysis. To50 μl of the serum was added 125 μl of methanol, and stirred, followedby centrifugation (10000 rpm, 2 minutes, 4° C.). To the supernatant wasadded an equal volume of a 10 mM aqueous ammonium acetate solution andthe resulting mixture was subjected to centrifugal filtration throughCentricut (W-MR, Kurabo Industries Ltd.). Then, 10 μl of the filtratewas analyzed by LC-MS/MS. The result is shown in FIG. 1.

As a result, the bioavailability (BA) in the case of orallyadministering the compound of Example 7 was found to be 18.4%. Thus, itwas confirmed that the compound of Example 7 is a prodrug having asuperior oral absorbability as compared with the oral administration ofthe compound of Example 14 (bioavailability: 2.7%).

Test Example 2 Inhibitory Activity Against MMP-13

As MMP-13, there was used one which had been prepared by geneticengineering (using a well-known human chondrocyte cDNA library as atemplate, cDNA fragments were amplified by PCR by the use of primers5′-AATAAGCTTCCACCATGCATCCAGGGGTCCTGGC-3′ (SEQ ID NO: 1) and5′-CCGCTCGAGTTACCCCAAATGCTCTTCAGG-3′ (SEQ ID NO: 2) and each of the cDNAfragments amplified was inserted in a vector pcDNA I, and the vector wasintroduced into COS-1 cells derived from Afurikamidorizaru kidney,followed by culture and the recovery of the supernatant of a culturemedium) on the basis of the well-known genetic base sequence of humanMMP-13 (J. Biol. Chem., 269 (24), 16766-16773 (1994)) and had beenactivated by maintaining the thus prepared MMP-13 at 37° C. for 2 hoursin the presence of 1 mM mercury 4-aminophenylacetate.

Inhibitory activity against human MMP-13 was measured according to themethod of C. G. Knight et al. (FEBS Lett., 296 (3), 263-266 (1992)).

That is, 45 μl of assay buffer (0.1M Tris-hydrochloric acid, 0.1M sodiumchloride, 0.01M calcium chloride, 0.05% Brigy 35, pH=7.5) was placed ina 96-well micro-titer plate for fluorometry, and 5 μl of a solution of atest compound in dimethyl sulfoxide was added thereto. Then, 25 μl ofthe activated human MMP-13 and 25 μl of a substrate solution obtained bydiluting a 1 mM solution of(7-methoxycoumarin-4-yl)acetyl-L-prolyl-L-leucyl-glycyl-L-leucyl-L-[N-(2,4-dinitrophenyl)-L-2,3-diaminopropiony]-L-alanyl-L-argininamide(MCA; SEQ ID NO: 3) (mfd. by Peptide Laboratories Co., Ltd.) in dimethylsulfoxide to a concentration of 80 μM with the assay buffer were addedthereto, and fluorescence (ex. 320 nm, em. 405 nm) was measured with afluorescence plate reader. After the micro-titer plate was maintained at37° C. for 12 hours to carry out the reaction, fluorescence was measuredwith the fluorescence plate reader to measure the residual enzymeactivity. The inhibitory activity against MMP-13 of the compound ofExample 14 was 44 nM as IC50 value.

Test Example 3 Pharmacological Test on Rat Partial-Meniscectomy Models

SD (IGS) male rats aged 6 weeks (purchased from Charles River JapanInc.) were used. The hair on the knee joint portion of right hind leg ofeach rat was shaved with a hair clipper under etherisation, and then theskin on the joint side of the lateral collateral ligament was incisedalong the ligament. Subsequently, the fascia was incised and the lateralcollateral ligament was resected in a length of about 3 mm. Thereafter,the medial meniscus was exposed and the matters adhering to the meniscuswere removed. The meniscus was picked up with tweezers and a part of themeniscus was cut off along the tweezers with microscissors. The fasciaand the skin were sutured. One week after the above treatment, theadministration of each test compound was started. The volume of the testcompound administered was 10 ml/kg (solvent: 0.5% methyl cellulose) andthe test compound was orally administered six times per week for 3weeks. After the body weight was measured, the shinbone of the righthind leg was collected and fixed in 10% neutral buffered formalin. Aparaffin section was prepared as a preparation. The shinbone wasembedded in paraffin at first and then sliced in a thickness of 6 μm,and the slice was stained with safranine O/Fast Green. A portion of theshinbone used for preparing the preparation was a portion 3 mm apartfrom the front where degeneration was most remarkable when visuallyobserved after the fixation in formalin. Evaluation was carried out asfollows by taking the decrease of the stainability of proteoglycan as anindication of chondrodegeneration. The cartilage portion inside theshinbone was divided into 9 portions as shown in the following drawingand the decrease of the stainability of proteoglycan in each portion isgiven a score in a blind test. The highest score of each portion wastaken as 1 and evaluation was expressed by numeral values on the basisof the percentage of decrease in the stainability (for example, a scoreof 0.25 in the case where the stainability was decreased in one-fourthof the portion). The total score of the 9 portions was taken as thescore (0 to 9) of the preparation. The average of scores for rats ineach group was calculated and the degree of chondrodegeneration of apathosis control group was taken as 100%. The chondrodegenerationinhibition rate of each compound was calculated by the followingequation:

Inhibition rate=1−(average score value of drug-treated group/score valueof control group)×100

As a result, the compound of Example 7 showed a chondrodegenerationinhibition rate of 52% at 50 mg/kg, indicating that the compound of thepresent invention has an excellent pharmacological action on arthrosisdeformans.

INDUSTRIAL APPLICABILITY

Owing to the present invention, it has become possible to provide anovel benzothiazin-3-one compound useful as the active ingredient of amedicine. That is, since the compound of the present invention exhibitsa good oral absorbability and is metabolized in a living body to give acompound having an excellent inhibitory activity against matrixmetalloproteases, it is useful as a therapeutic or preventive agent forarthrosis deformans, chondrodegenerative diseases such as chronicarticular rheumatism, the metastasis of cancerous cells, and the like oras an anti-inflammatory agent and the like. In addition, it has becomepossible to produce a 2-thiocarboxylic acid derivative or an opticallyactive 2-hydroxycarboxylic acid, which is an intermediate for producingthe above-mentioned benzothiazin-3-one compound in high yield.

SEQUENCE LISTING FREE TEXT

SEQ ID NO: 1: a PCR primerSEQ ID NO: 2: another PCR primerSEQ ID NO: 3: a synthetic peptide

1. A method of treating osteoarthritis or rheumatoid arthritisassociated with increased levels of a matrix metallo-proteinase whichcomprises administering to a patient an effective amount of a compoundof formula (1):

wherein n is 3 or 4; R is an ethyl group or a hydrogen atom; and R¹ is ahalogen atom, an alkoxy group, a haloalkyl group or a haloalkoxy group,or a pharmaceutically acceptable salt thereof.
 2. The method accordingto claim 1, wherein in the formula (1), R¹ is a fluorine atom, achlorine atom, a methoxy group, a trifluoromethyl group or atrifluoromethoxy group.
 3. The method according to claim 1, wherein inthe formula (1), the configuration relating to the carbon atom at the2-position is an S-configuration.
 4. The method according to claim 1,wherein in the formula (1), R is an ethyl group.
 5. The method accordingto claim 1, wherein in formula (1), R is a hydrogen atom.
 6. The methodaccording to claim 1, wherein the compound of the formula (1) is(−)-ethyl4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylate.7. The method according to claim 1, wherein the compound of the formula(1) is(−)-4-[2-(hydroxyamino)-2-oxoethyl]-2-[3-(4-methoxyphenyl)propyl]-3-oxo-3,4-dihydro-2H-1,4-benzothiazine-6-carboxylicacid.